Novel approaches to objectively assess shoulder function.

BACKGROUND

The purpose of this study was to evaluate the effectiveness of existing technologies implemented in a novel manner to objectively capture upper extremity function.

MATERIALS AND METHODS

Patients scheduled to undergo reverse shoulder arthroplasty were recruited for the study. Functional limb use was measured with triaxial accelerometers worn in the subjects' natural living environment. Functional reach area was captured by 3-dimensional motion analysis testing as subjects were asked to circumduct their limb, reaching as far as possible in a circular manner. Statistical testing (α ≤ .05) was performed by paired t tests to identify differences between limbs.

RESULTS

There was no difference in functional limb activity between sides for the lower (P = .497) or upper arm (P = .918) for inactivity time. Mean activity was greater for the uninvolved limb compared with the involved limb (lower arm, P = .045; upper arm, P = .005). Low-intensity activity was greater for the involved arm compared with the uninvolved arm (lower arm, P = .007; upper arm, P = .015), whereas high-intensity activity was greater for the uninvolved arm (lower arm, P = .013; upper arm, P = .005). Radius of the functional reach area was greater for the uninvolved limb compared with the involved limb (P = .006).

CONCLUSIONS

Novel methods of capturing function were effective in discerning differences in side-to-side abilities among patients scheduled to undergo reverse shoulder arthroplasty. These testing procedures may be used to capture function across a spectrum of shoulder diseases. These objective data are invaluable in assessing the impact of disease and recovery after intervention and obtaining reimbursement from third-party payers.