Elsevier

Clinical Biomechanics

Volume 21, Issue 8, October 2006, Pages 781-789
Clinical Biomechanics

Shoulder joint kinetics and pathology in manual wheelchair users

https://doi.org/10.1016/j.clinbiomech.2006.04.010Get rights and content

Abstract

Background

Manual wheelchair users rely heavily on their upper limbs for independent mobility which likely leads to a high prevalence of shoulder pain and injury. The goal of this study was to examine the relationship between shoulder forces and moments experienced during wheelchair propulsion and shoulder pathology.

Methods

Kinetic and kinematic data was recorded from 33 subjects with paraplegia as they propelled their wheelchairs at two speeds (0.9 and 1.8 m/s). Shoulder joint forces and moments were calculated using inverse dynamic methods and shoulder pathology was evaluated using a physical exam and magnetic resonance imaging scan.

Findings

Subjects who experienced higher posterior force (Odds Ratio (OR) = 1.29, P = 0.03), lateral force (OR = 1.35, P = 0.047), or extension moment (OR = 1.35, P = 0.09) during propulsion were more likely to exhibit coracoacromial ligament edema. Individuals who displayed larger lateral forces (OR = 4.35, P = 0.045) or abduction moments (OR = 1.58, P = 0.06) were more likely to have coracoacromial ligament thickening. Higher superior forces (OR = 1.05, P = 0.09) and internal rotation moments (OR = 1.61 P = 0.02) at the shoulder were associated with increased signs of shoulder pathology during the physical exam.

Interpretation

Specific joint forces and moments were related to measures of shoulder pathology. This may indicate a need to reduce the overall force required to propel a wheelchair in order to preserve upper limb integrity. Potential interventions include changes to wheelchair setup, propulsion training, or alternative means of mobility.

Introduction

It is well documented that manual wheelchair users (MWUs) with paraplegia have a high prevalence of shoulder pain and injury (Ballinger et al., 2000, Bayley et al., 1987, Boninger et al., 2001, Escobedo et al., 1997, Lal, 1998, Nichols et al., 1979, Pentland and Twomey, 1991, Sie et al., 1992, Subbarao et al., 1995). Estimates of shoulder pain among manual wheelchair users with paraplegia range from 30% (Ballinger et al., 2000) to 73% (Pentland and Twomey, 1991). A recent review article noted that shoulder pain is often a result of musculoskeletal pathology (Dyson-Hudson and Kirshblum, 2004). Another study reported that the acromioclavicular joint of the shoulder is the most susceptible to degenerative changes (Lal, 1998). MWUs rely on their upper extremity for independent mobility and other critical functions, and thus shoulder pain can be debilitating. One study found that pain was the only factor correlated with lower quality-of-life scores (Lundqvist et al., 1991).

“Overuse syndrome” has been described as one potential cause for pain in MWUs (Bayley et al., 1987, Nichols et al., 1979, Subbarao et al., 1995). Manual wheelchair propulsion places repeated loads on the upper limbs, with a stroke cycle time of less than a second. The shoulder joint experiences loading throughout the propulsion cycle (Cooper et al., 1999, Finley et al., 2004, Kulig et al., 1998, Mulroy et al., 2005, Rodgers et al., 1994). Ergonomics literature has previously identified a link between repetitive loading tasks and musculoskeletal disorders (Andersen et al., 2003, Frost et al., 2002, Leclerc et al., 2004, NIOSH, 1997). In a report of musculoskeletal disorders in the workplace, the National Institute for Occupational Safety and Health defined repetitive activities for the shoulder as activities that involve cyclical flexion, extension, abduction, or rotation of the shoulder joint (NIOSH, 1997). Wheelchair propulsion, while not an occupational task, fits this definition. The effects of repetition can be magnified when combined with awkward postures or loading of the upper extremity such as occurs in wheelchair propulsion (Andersen et al., 2002, Frost et al., 2002, NIOSH, 1997).

It is important to understand what biomechanical factors may predispose individuals to musculoskeletal shoulder pathology so that interventions can be developed. Task performance modification based on ergonomic analysis has proven effective in reducing risk factors for pain and upper extremity pathology in various work settings (Carson, 1994, Chatterjee, 1992, Orgel et al., 1992). Additionally, research has shown that many interventions can be applied to alter propulsion biomechanics (Boninger et al., 2005).

Previous studies have reported shoulder joint forces and moments during propulsion (Cooper et al., 1999, Finley et al., 2004, Kulig et al., 1998, Mulroy et al., 2005, Rodgers et al., 1994), but none have investigated a relationship to shoulder pathology. Since shoulder pain and injury are so common among MWUs, we hope to elucidate biomechanical risk factors for shoulder injury so that potential interventions can be developed. The goal of this study was to calculate shoulder forces and moments during two speeds of manual wheelchair propulsion and determine if biomechanics were related to shoulder pathology. We hypothesized that higher shoulder forces and moments during wheelchair propulsion would be correlated to a higher incidence of shoulder pathology as measured by physical examination and magnetic resonance imaging (MRI).

Section snippets

Subjects

Subjects were recruited from two primary sources: wheelchair vendors and discharge records from a large inpatient spinal cord injury (SCI) rehabilitation unit. A letter was sent to all potential subjects stating the purpose of the study and asking them to contact the laboratory if they wished to participate in the study. This recruiting method allowed us to identify all individuals with SCI, not just those currently being followed through regular clinic visits. The study was approved by our

Subjects

Thirty-three individuals, 23 males and 10 females, participated in this study. The subjects had an average height and mass of 1.74(SD = 0.1) m and 75.6(SD = 15.6) kg respectively. All subjects were between 20 and 70 years old and the average age of the group was 37.8(SD = 11.2) years. The average time since injury to the test date was 12.4(SD = 6.1) years ranging from 1 to 25 years. Only 4 out of 33 subjects reported experiencing pain while propelling their wheelchair in the month prior to testing.

Discussion

To our knowledge, this is largest study to investigate shoulder kinetics during wheelchair propulsion, and the first study to examine the relationship between kinetics and pathology. Our kinetic results are in general agreement with previous studies (Finley et al., 2004, Kulig et al., 1998, Mulroy et al., 2005). Kulig et al. reported significant increases in shoulder forces and moments with faster speed (Kulig et al., 1998). They also observed the same directional force and moment components

Conclusions

Individuals who experienced higher directional shoulder forces and moments were more likely to exhibit coracoacromial arch pathology on MRI and discomfort during a physical exam. Therefore, researchers and clinicians should work to reduce the forces and moments experienced at the shoulder during wheelchair propulsion. The potential exists to modify wheelchair design and set up or propulsion biomechanics in order to reduce the force required to propel the wheelchair, thereby reducing the loading

Acknowledgements

This research was supported by the National Institute on Disability and Rehabilitation Research (Grant # H133A011107), the Veterans Affairs Rehabilitation Research and Development Center (Grant # B3057R and B3142C), and a National Science Foundation Graduate Research Fellowship.

References (40)

  • M.L. Boninger et al.

    Shoulder imaging abnormalities in individuals with paraplegia

    Journal of Rehabilitation R&D

    (2001)
  • M. Boninger et al.

    Pushrim biomechanics and injury prevention in spinal cord injury: recommendations based on CULP-SCI investigations

    Journal of Rehabilitation Research and Development

    (2005)
  • R. Carson

    Reducing cumulative trauma disorders: use of proper workplace designs

    American Association of Occupational Health Nurses Journal

    (1994)
  • D. Chatterjee

    Workplace upper limb disorders: a prospective study with intervention

    Occupational Medicine

    (1992)
  • R.A. Cooper et al.

    Methods for determining three-dimensional wheelchair pushrim forces and moments— a technical note

    Journal of Rehabilitation Research and Development

    (1997)
  • R. Cooper et al.

    Glenohumeral joint kinematics and kinetics for three coordinate system representations during wheelchair propulsion

    Amercian Journal of Physical Medicine and Rehabilitation

    (1999)
  • K.A. Curtis et al.

    Development of the Wheelchair User’s Shoulder Pain Index (WUSPI)

    PARAPLEGIA

    (1995)
  • C.P. DiGiovine et al.

    Dynamic calibration of a wheelchair dynamometer

    Journal of Rehabilitation Research and Developement

    (2001)
  • T. Dyson-Hudson et al.

    Shoulder pain in chronic spinal cord injury, Part I: Epidemiology, etiology, and pathomechanics

    The Journal of Spinal Cord Medicine

    (2004)
  • E. Escobedo et al.

    MR imaging of rotator cuff tears in individuals with paraplegia

    American Journal of Roentology

    (1997)
  • Cited by (207)

    • Glenohumeral joint dynamics and shoulder muscle activity during geared manual wheelchair propulsion on carpeted floor in individuals with spinal cord injury

      2022, Journal of Electromyography and Kinesiology
      Citation Excerpt :

      Previous studies have indicated that significantly higher hand-rim forces and moments are necessary to overcome the greater rolling resistance of carpeted floor compared to a hard floor (e.g. tile terrain), which could increase the upper extremity joint loading during propulsion and lead to secondary injuries (Koontz et al., 2005; Hurd et al., 2008). The geared wheels have proven to significantly decrease these joint forces and moments, which may ultimately reduce the risk of musculoskeletal injuries common in wheelchair users (Boninger et al., 2005; Mercer et al., 2006; Requejo et al., 2008). Future applications of this geared wheel technology may prove to be beneficial for manual wheelchair users during the start-up phase in addition to carpet, ramps, and uneven terrain.

    View all citing articles on Scopus
    View full text