Novel approaches to objectively assess shoulder function

Monitoring daily shoulder activity before and after reverse total shoulder arthroplasty using inertial measurement units

BACKGROUND

The purpose of this study was to use at-home, portable, continuous monitoring technologies to record arm motion and activity preoperatively and postoperatively after reverse total shoulder arthroplasty (RTSA).

METHODS

Thirty-three patients indicated for RTSA were monitored preoperatively and 3 and 12 months postoperatively. Inertial measurement units were placed on the sternum and upper arm of the operative limb, recording humeral motion relative to the torso for the duration of a waking day. Elevation events per hour (EE/h) > 90°, time spent at >90°, and activity intensity were calculated and compared between time points. Patient-reported outcome measures were also collected at all time points.

RESULTS

At 3 (P = .040) and 12 (P = .010) months after RTSA, patients demonstrated a significantly greater number of EE/h > 90° compared with preoperatively. There were no significant differences (P ≥ .242) in the amount of time spent at different elevation angles at any time point or in arm activity intensity. Overall, 95% of the day was spent at elevation angles < 60°, and 90% of the day was spent in a low- or moderate-intensity state. Pearson correlations demonstrated relationships between forward elevation and the number of EE/h (r = 0.395, P = .001) and the number of EE/h > 90° (r = 0.493, P < .001).

CONCLUSION

After RTSA, patients significantly increase the frequency of arm elevation to higher angles. However, we found no differences in the amount of time spent at different elevation angles. Overall, after RTSA, >95% of the day was spent at elevation angles < 60° and <1% of the day was spent at >90° of elevation.

Accelerometry evaluation of shoulder movement and its association with patient-reported and clinical outcomes following reverse total shoulder arthroplasty

BACKGROUND

Accelerometers provide a new method to objectively measure recovery of movement and physical activity in patients following reverse total shoulder arthroplasty (RTSA) and may overcome common limitations associated with patient-reported outcome measures (PROMs). The aim of this study was to assess changes in upper limb movement using accelerometers following RTSA and investigate their association with other clinical outcome measures.

METHODS

Thirty-six patients who underwent RTSA wore accelerometers on both wrists and arms for 3 days at 3, 6, and 12 months postsurgery. PROMs (Constant score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, visual analog scale for pain, Single Assessment Numerical Evaluation, Shoulder Activity Level) and isometric shoulder strength were also assessed. Accelerometer outcomes were calculated to quantify counts of forearm and arm activity and the contribution of both arms to activity (limb symmetry and magnitude ratio). Changes and differences in all clinical measures and objective movement measures were evaluated with within-subjects analysis of variance. Correlations between limb activity and other clinical measures were investigated using Spearman correlation coefficients.

RESULTS

Objective movement of the operated arm increased from 3-6 months postsurgery (P = .004), but not from 6-12 months (P = .240). Limb asymmetries were observed at 3 and 6 months and improved by 12 months postsurgery. No associations were demonstrated between PROMs and objective upper limb movement at 12 months postsurgery.

DISCUSSION

Despite early recovery of function and pain relief assessed by PROMs, objective movement using accelerometers showed delayed recovery of the operated arm postoperatively, before normalizing by 12 months postsurgery. Accelerometers provide a unique insight into functional recovery following RTSA.

Variations in glenohumeral movement control when implementing an auditory feedback system: A pilot study

Introduction: Human motor control requires a learning process and it can be trained by means of various sensory feedback sources.Objective: To determine variations in glenohumeral movement control by learning in young adults exposed to an auditory feedback system while they perform object translation tasks classified by difficulty level.Materials and methods: The study involved 45 volunteers of both sexes (22 women), aged between 18 and 32 years. Glenohumeral movement control was measured by means of the root mean square (RMS) of the accelerometry signal, while task execution speed (TES) was measured using an accelerometer during the execution of the task according to its difficulty (easy, moderate and hard) in four stages of randomized intervention (control, pre-exposure, exposure-with auditory feedback, and post-exposure).Results: Statistically significant differences (p<0.001) were found between the pre-exposure and exposure stages and between pre-exposure and post-exposure stages. A significant increase (p <0.001) in TES was identified between the pre-exposure and exposure stages for tasks classified as easy and hard, respectively.Conclusion: The use of an auditory feedback system in young adults without pathologies enhanced learning and glenohumeral movement control without reducing TES. This effect was maintained after the feedback, so the use of this type of feedback system in healthy individuals could result in a useful strategy for the training of motor control of the shoulder.

Outcome Measures of Free-Living Activity in Spinal Cord Injury Rehabilitation

PURPOSE OF REVIEW

The purpose of this article was to describe the utilization of body worn activity monitors in the SCI population and discuss the challenges of using body worn sensors in rehabilitation research.

RECENT FINDINGS

Many activity monitor-based measures have been used and validated in the SCI population including stroke number, push frequency, upper limb activity counts and wheelchair propulsion distance measured from a sensor attached to the wheelchair.

SUMMARY

The ability to accurately measure physical activity in the free-living environment using body-worn sensors has the potential to enhance the understanding of barriers to adequate activity and identify possible effective interventions. As the use of activity monitors used in SCI rehabilitation research continues to grow, care must be taken to overcome challenges related to participant adherence and data quality.

Patient-Reported and Objectively Measured Function Before and After Reverse Shoulder Arthroplasty

BACKGROUND AND PURPOSE

Documenting functional outcomes after reverse shoulder arthroplasty (RSA) is critical to advancing patient care. The interplay been self-reported and objectively measured outcome measures has not been widely described. The utilization of wearable devices to document upper extremity limb activity is a new approach for objectively measuring outcomes. Therefore, the purpose of this study was to evaluate changes in pain, and self-reported function and objectively measured limb activity after RSA. We also assessed the influence of pain on self-reported function and objectively measured limb activity to determine the impact of pain on outcomes after RSA.

MATERIALS

This study implemented a prospective, repeated-measures design. Fourteen patients undergoing RSA underwent testing before surgery, and 2 and 12 months after surgery. Patient-reported instruments included pain, Disabilities of Arm, Shoulder and hands (DASH), and physical component summary (PCS) of the 36-Item Short Form Health Survey. Objective limb activity (mean activity value, m/s/min epoch; inactive time, %; low activity, %; and high activity, %) was captured with triaxial accelerometers worn on the upper and lower arm. A repeated-measures ANOVA tested for differences across time. The Spearman rank-order correlation was calculated to evaluate the influence of pain on DASH, PCS scores, and mean limb activity.

RESULTS

Patient-reported measures improved after surgery (pain, P < .01; DASH, P < .01; PCS, P = .01). No change in limb activity was found at 1 year compared with preoperative values for mean (forearm, P = 1.00; arm, P = .36), inactivity (forearm, P = .33; arm, P = .22), low (forearm, P = .77; arm, P = .11) or high (forearm, P = 1.00; arm, P = .20) activity. There was a relationship between pain and DASH scores 1 year after surgery (P = .04) but not before surgery (P = .16), or 2 months after surgery (P = .30). There was no relationship between pain and PCS scores at any time point (preoperative, P = .97; 2 months, P = .21; 1 year, P = .08) nor pain and limb activity (forearm: preoperative, P = .36; 2 months, P = .67; 1 year, P = .16; arm: preoperative, P = .97; 2 months, P = .59; 1 year, P = .51).

CONCLUSIONS

RSA reduced pain and enhanced patient-perceived function. Objectively measured upper extremity limb activity is not different 1 year after surgery compared with preoperative levels.

LEVEL OF EVIDENCE

III.

Comparing daily shoulder motion and frequency after anatomic and reverse shoulder arthroplasty

BACKGROUND

Both anatomic (TSA) and reverse total shoulder arthroplasty (RTSA) are common interventions for glenohumeral arthrosis, with the goal of relieving pain and restoring mobility. Understanding shoulder arthroplasty motion and frequency is of interest in evaluating effectiveness and in predicting bearing wear for implant development and optimization. The purpose of this study was to measure and compare the total daily shoulder motion of patients after TSA and RTSA.

METHODS

Thirty-six human subjects who had undergone shoulder arthroplasty wore a custom instrumented garment that tracked upper extremity motion for the waking hours of 1 day. The 3-dimensional orientation of each humeral sensor was transformed with respect to the torso to calculate total joint motion and frequency, with comparison of TSA to RTSA. In addition, the yearly motion of the shoulder was extrapolated.

RESULTS

The majority of shoulder motion occurred below 80° of elevation (P < .001), totaling on average 821 ± 45 and 783 ± 27 motions per hour for TSA and RTSA, respectively. Conversely, elevations >80° were significantly less frequent, totaling only 52 ± 44 (P < .001) and 38 ± 27 (P < .001) motions per hour for TSA and RTSA, respectively. No significant differences were detected between TSA and RTSA shoulders (P = .22) or their respective contralateral asymptomatic sides (P = .64, P = .62). When extrapolated, it was estimated that each TSA and RTSA shoulder elevated above 60° approximately 1 million and 0.75 million cycles per year, respectively.

DISCUSSION

Mean shoulder motions after TSA or RTSA were not significantly different from the contralateral asymptomatic side. In addition, no significant differences were detected in shoulder motion or frequency between TSA and RTSA.

Alteration and recovery of arm usage in daily activities after rotator cuff surgery

BACKGROUND

The objective measurement of dominant/nondominant arm use proportion in daily life may provide relevant information on healthy and pathologic arm behavior. This prospective case-control study explored the potential of such measurements as indicators of upper limb functional recovery after rotator cuff surgery.

METHODS

Data on dominant/nondominant arm usage were acquired with body-worn sensors for 7 hours. The postsurgical arm usage of 21 patients was collected at 3, 6, and 12 months after rotator cuff surgery in the sitting, walking, and standing postures and compared with a reference established with 41 healthy subjects. The results were calculated for the dominant and nondominant surgical side subgroups at all stages. The correlations with clinical scores were calculated.

RESULTS

Healthy right-handed and left-handed dominant arm usage was 60.2% (±6.3%) and 53.4% (±6.6%), respectively. Differences in use of the dominant side were significant between the right- and left-handed subgroups for sitting (P = .014) and standing (P = .009) but not for walking (P = .328). The patient group showed a significant underuse of 10.7% (±8.9%) at 3 months after surgery (P < .001). The patients recovered normal arm usage within 12 months, regardless of surgical side. The arm underuse measurement was weakly related to function and pain scores.

CONCLUSION

This study provided new information on arm recovery after rotator cuff surgery using an innovative measurement method. It highlighted that objective arm underuse measurement is a valuable indicator of upper limb postsurgical outcome that captures a complementary feature to clinical scores.