Technical Note
Stuart M. McGill, Jacek Cholewicki
The term "stability," as used in the field of biomechanics, remains undefined in many clinical cases. This fact can impede the design of therapies intended to enhance joint stability. In fact, Fritz et al, in a review on lumbar instability, concluded that, "At present, much controversy exists regarding the proper definition of the condition, the best diagnostic methods, and the most efficacious treatment approaches." Some progress has been made in the biomechanics field toward the formulation and implementation of stability in musculoskeletal linkages and joints.
The purpose of this review is to synthesize and interpret the biomechanical foundation for stability while avoiding mathematical complexity, to demonstrate the notion of stability using specific musculoskeletal examples, and to propose the next logical steps to full utilization of the stability concept for optimal rehabilitation. This review is not intended as a scholarly treatise but rather as a short commentary aimed at providing clinicians with a vantage point for making clinical decisions. Finally, because we are spine biomechanists, and because the original work defining the mechanics of stability of musculoskeletal systems used the spine as an example, this article emphasizes the spine in its examples. J Orthop Sports Phys Ther. 2001;31(2):96-100.
Key Words: biomechanics, stability
View Abstract 
View Full Article
Research Report
Heather A. Hankin, Sam Kegerreis, James M. Rice, Tara Spencer, Teddy W. Worrell
Study Design: Descriptive, ex post facto.
Objectives: To determine the proportion of physical therapy outpatients with pain who exhibit various pain behavior profiles, and to determine whether there are differences in functional disability across the profiles.
Background: Physical therapists treat many patients who have chronic pain. Research suggests that early identification and multidisciplinary treatment are effective and economical for these patients. The Multidimensional Pain Inventory (MPI) and the Pain Disability Index (PDI) are potential screening tools that could be used in physical therapy clinics to determine which patients should be referred for multidisciplinary treatment.
Methods and Measures: MPI and PDI data were gathered on 57 physical therapy outpatients (mean age 44.3 ± 14.5 years, 22 men and 35 women) with pain of 3 or more months duration. ANOVA was used to analyze differences in mean PDI scores across the MPI profiles.
Results: Of all patients, 42.1% fit the Adaptive Coper profile, 29.8% fit the lnterpersonally Distressed profile, and 28.1% fit the Dysfunctional profile. There were significant differences in PDI scores among profile groups. Post hoc analysis showed that the PDI scores of the Adaptive Coper and lnterpersonally Distressed groups were different from the Dysfunctional group, but that there was no difference between the Adaptive Coper and Interpersonally Distressed groups.
Conclusions: Many patients in outpatient physical therapy settings exhibit behavioral, affective, and cognitive characteristics associated with chronic pain. Thirty-three patients (57.9%) had MPI profiles (interpersonally distressed and dysfunctional) that suggest they might benefit from multidisciplinary treatment. J Orthop Sports Phys Ther. 2001;31(2):90-95.
Key Words: chronic pain, Multidimensional Pain Inventory, Pain Disability Index
View Abstract
View Full Article
Research Report
Marilyn Moffat, Elaine Rosen, Sandra Rusnak-Smith
Study Design: Cadaver dissection to study the anatomy of the scaleni muscles and surrounding structures.
Objectives: To analyze in depth the anatomy of the scaleni muscles and surrounding structures, and to further document anatomical variations which have been reported in the literature.
Background: The literature reported variations in the attachments of the scaleni muscles, as well as the presence of a scalenus minimus muscle. The importance of these muscles in the respiratory and musculoskeletal systems led us to study these muscles with dissection.
Methods and Measures: We performed anatomical dissection on 10 cadavers. The findings from the cadavers were analyzed and reported.
Results: The attachments of the 3 primary scaleni muscles (anterior, medius, and posterior) were variable. The actual width of the scaleni muscles (anterior, medius, and posterior) at the C6 tubercle and at the first rib also varied. A scalenus minimus was present in one cadaver and presumably present in 2 others.
The scalenus anterior muscle arose in 20% of the specimens from C3 to C6, in 30% of the specimens from C3 to C7, in 20% of the specimens from C4 to C5, and in 30% of the specimens from C4 to C6. The scalenus anterior muscle arose from C3 in 50% of the dissections. An attachment to C7 was observed in 30% of the cadavers. The widths of the scalenus anterior muscles at their insertion were between 8 and 17 mm. The scalenus medius muscle arose in 40% of the specimens from C2 to C6. In 60% of the cadavers, the scalenus medius muscle had an attachment to C7. Fifty percent of the scalenus medius muscles arose from C2 and 50% also had an origin from C1. The widths of the scalenus medius muscles at their insertion were between 10 and 20 mm with a mean of 15.5 mm. Fifty percent of the scalenus posterior muscles arose from C4 to C6 and 50% arose from C5 to C6.
Conclusions: Variations were found in the attachments and the size of the scaleni muscles. These variations may effect the size of the scalene triangle, and thus, may potentially result in varied signs and symptoms in patients who have cervical, thoracic, and rib dysfunctions. Clinical implications were postulated. J Orthop Sports Phys Ther. 2001;31(2):70-80.
Key Words: anatomical variations, scalene triangle, scaleni muscles, supraclavicular triangle, thoracic inlet
View Abstract
View Full Article
Research Report
Anthony C. Bare, Yong Bradley, Capt David A. Browder, Ryan T. Girrbach, Karlene L. Guffie, Pamela K. Levangie, Lawrence N. Masullo, Josef H. Moore, Timothy W. Flynn
Study Design: Case-control nonexperimental design.
Objectives: To compare flexural wave propagation velocity (FWPV) and tibial bone mineral density (BMD) in women with and without tibial bone stress injuries (BSls).
Background: Physical therapists, particularly in military and sports medicine settings, routinely diagnose and manage stress fractures or bone stress injuries. Improved methods of preparticipation quantification of tibial strength may provide markers of BSI risk and thus potentially reduce morbidity.
Methods and Measures: Bone mineral density, FWPV, bone geometry, and historical variables were collected from 14 subjects diagnosed with tibial BSls and 14 age-matched controls; all 28 were undergoing military training.
Results: No difference was found between groups in FWPV and tibial BMD when analyzed with t tests (post hoc power = 0.89 and 0.81, respectively). Furthermore, no difference was found in tibial length, tibial width, femoral neck BMD, and lumbar spine BMD among the groups. There were no differences between the 2 groups in smoking history, birth control pill use, and onset of menarche. Finally, sensitivity and positive likelihood ratios for FWPV (0.14 and 0.63), tibial BMD (0.0 and 0.0), and lumbar BMD (0.18 and 2.0) were low, while specificity was high (0.77, 0.93, and 0.91, respectively).
Conclusion: Current bone analysis devices and methods may not be sensitive enough to detect differences in tibial material and structure; local stresses on bone may be more important in the development of BSls than the overall structural stiffness. J Orthop Spots Phys Ther. 2001;31(2):54-69.
Key Words: bone stiffness, overuse injuries, risk factors, stress fractures
View Abstract
View Full Article
Research Report
Michael P. Johnson, Andrew R. Karduna, Philip W. McClure
Study Design: Test-retest repeated measures and correlational design.
Objectives: To examine the reliability and validity of a "modified" digital inclinometer to assess scapular upward rotation during humeral elevation in the scapular plane
Background: Evidence exists that scapular motion is related to shoulder pathology; however, evaluation and treatment planning for shoulder rehabilitation often fails to include an objective assessment of scapular motion.
Methods and Measures: Two-dimensional measurements by the inclinometer were taken with the arm in a static position. These data were compared to 3-dimensional measurements obtained using a magnetic tracking device with the arm fixed and during arm movement. Both methods were used to assess scapular upward rotation positions with the arm at rest and at 60°, 90°, and 120° of humeral elevation in the scapular plane. Both scapulae were tested on a total of 39 subjects, 16 with shoulder pathology and 23 without. Reliability was assessed using repeated measurements from the inclinometer. Validity was assessed using 2 separate comparisons: inclinometer and magnetic tracking device under static arm conditions and inclinometer and magnetic tracking device during active arm elevation. Reliability and validity were assessed at all 4 arm positions.
Results: lntraclass correlation coefficients (ICC [3,1]) varied from 0.89 to 0.96. Pearson Product Moment correlation coefficients, used to assess validity of the static inclinometer, varied from r = 0.74 to 0.92 compared with the static magnetic tracking measures, and from r = 0.59 to 0.73 compared with the active magnetic tracking measures taken during arm elevation.
Conclusions: The "modified" digital inclinometer demonstrated good to excellent intrarater reliability and good to excellent validity when measuring scapular upward rotation during static positions of humeral elevation in the scapular plane. J Orthop Sports Phys Ther. 2001;31(2):81-89.
Key Words: inclinometer, measurement, scapular kinematics, scapular plane, three-dimensional
View Abstract
View Full Article
