How Does Level and Type of Experience Affect Measurement of Joint Range of Motion?

Accuracy amidst errors: Evaluating a commercially available wearable sensor system and its associated calibration procedures for monitoring sagittal knee motion in patients undergoing total knee arthroplasty

BACKGROUND

Commercially available wearable sensors monitoring knee range of motion (ROM) are gaining traction in orthopaedics, but few studies validate against optical motion capture (MOCAP) in total knee arthroplasty (TKA) patients. Furthermore, wearable calibration is essential for accurate measurements, yet few investigations evaluate calibration and ROM accuracy. This study assessed one commercial wearable sensor system's calibration (goniometric versus MOCAP) and sagittal knee angle computation accuracy in TKA patients during activities.

METHODS

Twenty TKA patients were recruited (5 lost to follow-up). Following a sensor tutorial (MotionSense, Stryker, Mahwah, NJ), participants self-applied sensors for pre-TKA data capture. TKA was then performed by one surgeon followed by identical post-TKA data captures. MOCAP and wearable sensor data were collected during activities. MOCAP sagittal knee angles (θMOCAP) were compared to two wearable sensor knee angles: 1) θCalGoni = goniometric calibration, 2) θCalMOCAP = MOCAP calibration. Two-way ANOVAs evaluated the impact of time (pre-TKA vs. post-TKA) and calibration type (goniometry vs. MOCAP) on calibration angles and wearable sensor error. Variance equality tests compared pre-TKA vs. post-TKA and goniometric vs. MOCAP calibration.

RESULTS

No significant differences were noted pre-TKA vs. post-TKA. Calibration angles differed significantly with goniometry yielding significantly more error than MOCAP. MOCAP calibration reduced error below clinically acceptable levels (<5°) during activities and with significantly less error variance.

CONCLUSION

MOCAP calibration significant improved accuracy of knee angle computations to acceptable levels (<5°). Accordingly, these wearables are suitable for continuous knee ROM monitoring after calibrating with correct angles, Future studies should investigate specific activities and sensor misplacement on angle measurements.

Medium-term results of inlay vs. onlay humeral components for reverse shoulder arthroplasty: a New Zealand Joint Registry study

BACKGROUND

The purpose of this study was to compare medium-term results of inlay and onlay humeral components in reverse shoulder arthroplasty (RSA). Specifically, we report differences in revision rate and functional outcomes between the 2 designs.

METHODS

The 3 most used inlay (in-RSA) and onlay (on-RSA) implants by volume from the New Zealand Joint Registry were included in the study. In-RSA was defined as having a humeral tray that recessed within the metaphyseal bone, whereas on-RSA was defined as having a humeral tray that rested on the epiphyseal osteotomy surface. The primary outcome was revision up to 8 years postsurgery. Secondary outcomes included the Oxford Shoulder Score (OSS), implant survival, and revision cause for in-RSA and on-RSA as well as individual prostheses.

RESULTS

There were 6707 patients (5736 in-RSA; 971 on-RSA) included in the study. For all causes, in-RSA demonstrated a lower revision rate compared to on-RSA (revision rate/100 component years: in-RSA 0.665, 95% confidence interval [CI] 0.569-0.768; on-RSA 1.010, 95% CI 0.673-1.415). However, the mean 6-month OSS was higher for the on-RSA group (mean difference 2.20, 95% CI 1.37-3.03; P < .001). However, this was not clinically significant. At 5 years, there were no statistically or clinically significant differences between the 2 groups with respect to the OSS.

CONCLUSION

The medium-term survival of in-RSA was higher than that of on-RSA. However, functional outcomes at 6 months were better for on-RSA compared to in-RSA. Further follow-up is required to understand the long-term survivorship and functional outcomes between these designs.

Validity and Reliability of Inertial Measurement Units in Active Range of Motion Assessment in the Hip Joint

Measuring joint range of motion has traditionally occurred with a universal goniometer, inclinometer, or expensive laboratory systems. The popularity of the inertial measurement unit (IMU) is growing, enabling the small and even single portable device to measure the range of motion. Until now, they were not used to assess hip joint range of motion. Our study aimed to check the validity of IMUs in assessing hip range of motion and compare them to other measurement devices-universal goniometer and inclinometer. Twenty participants completed three hip movements (flexion in standing and prone internal and external rotation) on both hips. Two testers independently assessed each movement with a goniometer, digital inclinometer, and IMU at different time points. To assess the agreement of active hip ROM between devices, Intraclass Correlation Coefficient (ICC) and Bland-Altman analysis were used. Furthermore, inter-rater and intra-rater reliability were also assessed by using ICC and Bland-Altman analysis. Limits of agreement (LOA) were calculated using Bland-Altman plots. The IMU demonstrated good to excellent validity (ICC: 0.87-0.99) compared to the goniometer and digital inclinometer, with LOAs < 9°, across all tested movements. Intra-rater reliability was excellent for all devices (ICC: 0.87-0.99) with LOAs < 7°. However, inter-rater reliability was moderate for flexion (ICC: 0.58-0.59, LOAs < 22.4) and poor for rotations (ICC: -0.33-0.04, LOAs < 7.8°). The present study shows that a single inertial measurement unit (RSQ Motion, RSQ Technologies, Poznan, Poland) could be successfully used to assess the active hip range of motion in healthy subjects, comparable to other methods accuracy.

Development of Supportive-Educative Range of Motion Exercise for Post-stroke Patients: A Pilot Study

The purpose of this pilot study was to assess of home care intervention on post-stroke related outcome of range of motion and muscle strength. Sample in 40 participants were divided into the intervention group and control group and included in this study according to the following criteria: post-stroke period of <12 months with hemiparesis, age of ≥18 years, and willingness to participate in the study. The intervention was carried out by nurses by providing education for 2 consecutive days and mentoring for 5 consecutive days, while the control group was given standard care and measured using a grip track, handheld dynamometer, and goniometer examination on June to September 2019. For the intervention group, paired t-test analysis confirmed a significant increase in the mean upper extremity muscle strength before (35.770 ± 46.063) and after (51.073 ± 50.866) the 7 day intervention ( p = .002), whereas the control group showed a value 36.570 ± 33.684 and then 31.400 ± 31.760 p = .256 and lower extremity strength before (3.627 ± 1.585) and after (4.365 ± 1.698) the 7-days intervention ( p = .000), whereas the control group showed a value 3.657 ± 1.671 and then 4.043 ± 1.849 p = .013. Almost all the items assessed from Range of Motion (ROM) in the upper and lower extremities showed a significant increase ( p < .05). Supportive-educative ROM exercise significantly contributed to an increase in the average muscle strength and ROM in post-stroke patients.

Deltoid fatigue part 2: a longitudinal assessment of anatomic total shoulder arthroplasty over time

BACKGROUND

Gradual loss of overhead range of motion (ROM) has been observed after reverse shoulder arthroplasty (RSA). It remains unclear if this is caused by the effect of RSA design on muscle fiber lengthening or is part of the natural aging process of the shoulder musculature. Although studies have attempted to evaluate deltoid fatigue after RSA, there is a paucity of literature evaluating this effect after anatomic shoulder arthroplasty (aTSA), which would be expected to occur due to aging alone. The purpose of this study is to evaluate the effect of time on overhead ROM after aTSA and compare this with previous data on a similar cohort of RSAs. We hypothesized that overhead ROM would decrease gradually over time in both groups without differences between prosthesis types.

METHODS

A retrospective review of 384 aTSAs without complications was performed over a 10-year period. All shoulders were treated for primary osteoarthritis using a single implant system. Patients were evaluated longitudinally at multiple postoperative time points. At least 1 follow-up visit was between 1 and 2 years postoperatively and another at least 5 years after surgery. ROM and patient reported outcome measures (PROMs) were evaluated using linear-mixed models for repeated measures. These results were compared with a previously evaluated cohort of 165 well-functioning RSAs analyzed using the same methodology.

RESULTS

Primary aTSA shoulders were observed to lose 0.7° of abduction per year starting 1 year postoperatively (P = .001). Smaller losses were observed in external rotation (-0.3°/yr, P = .06) and internal rotation (-0.04/yr, P < .001). However, no significant losses were observed in forward elevation (P = .8). All PROMs diminished slowly over time, but these changes did not exceed the minimally clinically important difference when modeled over 10 years (Simple Shoulder Test -0.08/yr, P < .001; American Shoulder Elbow Surgeons -0.5/yr, P < .001; University of California Los Angeles Shoulder Score -0.2/yr, P < .001). When compared with a similarly analyzed cohort of RSAs, overhead ROM decreased at a slower rate in the aTSA cohort (abduction -0.7° vs. -0.8°/yr, P = .9; FE -0.06° vs. -0.8°/yr, P = .05).

DISCUSSION

In the well-functioning aTSA, gradual loss of ROM occurs in all planes of motion except forward elevation. However, these losses are small and have little meaningful impact relative to minimally clinically important difference thresholds on PROMs. Progressive loss of abduction seen in both aTSA and RSA is likely secondary to aging of the periscapular and rotator cuff musculature. When compared with RSA, loss of motion after aTSA was statistically similar, calling into question the belief that RSA-induced deltoid fatigue leads to loss of overhead motion over time.

Preoperative factors associated with loss of range of motion after reverse shoulder arthroplasty

BACKGROUND

Reverse total shoulder arthroplasty (RTSA) is a successful procedure, often allowing patients to achieve better range of motion (ROM) compared with their preoperative baseline. However, there is a subset of patients who either fail to improve or lose ROM postoperatively. These patients are at increased risk of poor satisfaction and patient-reported outcomes. To date, characteristics of this subset of patients have not been well described. The purpose of this study is to determine risk factors associated with loss of ROM after primary RTSA.

METHODS

A retrospective review using a commercial international RTSA database (Exactech Inc., Gainesville, FL, USA) of patients who underwent primary RTSA between 2007 and 2017 was performed. A total of 123 (7.7%) shoulders lost ≥10° of forward elevation (FE) (group 1, P₁) and 183 (11.4%) lost ≥10° of external rotation (ER) (group 2, P₂). Univariate and multivariate analyses were performed comparing these patients with control cohorts to evaluate risk factors for loss of motion.

RESULTS

Better preoperative abduction, FE, ER, and internal rotation were each associated with greater loss of FE (P₁ < .001) and ER (P₂ < .001) postoperatively. Higher preoperative Simple Shoulder Test (P₁ < .001, P₂ < .001), Constant (P₁ < .001, P₂ < .001), Shoulder Pain and Disability Index (P₁ < .001, P₂ < .001), American Shoulder Elbow Surgeons (P₁ < .001), and University of California at Los Angeles (P₁ < .001) scores were also strongly associated with loss of ROM postoperatively. Other factors associated with a higher risk of losing ROM included a diagnosis of irreparable rotator cuff tear (P₁ = .038), rotator cuff arthropathy (P₁ = .017, P₂ ≤ .001), and inflammatory arthropathy (P₁ = .021). After multivariate analysis, higher preoperative FE (P₁ < .001), internal rotation (P₁ = -.018), and weight (P₁ = .008) remained significant predictors of loss of FE. Better preoperative FE (P₂ = .003), ER (P₂ < .001), and University of California at Los Angeles score (P₂ < .001) remained significant predictors of loss of ER. Patients who lost FE or ER were more likely to report lower satisfaction scores than their counterparts who did not lose ROM (P₁ < .001, P₂ < .001).

CONCLUSION

Patients with greater preoperative shoulder ROM or higher patient-reported outcomes are at higher risk of losing ROM after primary RTSA. They are also at higher risk of reporting lower postoperative satisfaction, though the majority were still satisfied. Surgeons should strongly counsel patients with well-preserved preoperative function on the risk of loss of ROM.

Deltoid fatigue: a longitudinal assessment of reverse shoulder arthroplasty over time

BACKGROUND

Studies evaluating the mid-term performance of reverse shoulder arthroplasty (RSA) have identified a drop in the Constant-Murley score between 6 and 8 years after surgery, which is most affected by a loss of forward elevation and strength. Alterations of the deltoid length and moment arm after RSA lead to nonphysiological stress on the deltoid muscle. Concern has arisen that the long-term implications of increased deltoid work may be causing "deltoid fatigue." The purpose of this study was to evaluate the long-term effects of RSA on overhead range of motion (ROM) and validate the hypothesis of deltoid fatigue.

METHODS

We performed a retrospective review of 165 RSAs over a 5-year period. Diagnoses were limited to cuff tear arthropathy, osteoarthritis with rotator cuff deficiency, and irreparable rotator cuff tear. All procedures were performed using a single implant system. Patients were evaluated longitudinally at multiple time points. They were required to undergo a minimum of 3 follow-up visits, with at least 1 visit at >5 years. ROM and patient-reported outcome measures were evaluated using linear mixed models for repeated measures to evaluate changes in outcome measures over time. A secondary analysis was performed to assess the influence of patient demographic factors on observed changes in ROM and patient-reported outcome measures.

RESULTS

Primary RSA shoulders were observed to lose 0.8° of forward elevation and abduction per year starting at 1 year postoperatively (P = .006), without a significant drop at mid-term follow-up. No significant change in external or internal rotation was observed. Male patients and patients with a diagnosis of osteoarthritis with rotator cuff deficiency showed greater baseline overhead ROM at 1 year postoperatively, but the subsequent rates of functional decline were similar regardless of age, sex, or indication.

DISCUSSION

This study challenges the previous theory of deltoid fatigue resulting in a significant loss of overhead ROM beginning 6-8 years after index arthroplasty. However, a slower progressive decline in overhead ROM in well-functioning RSA shoulders was observed, averaging 0.8° of overhead ROM per year. This progressive deterioration occurs at a slightly greater rate than that observed in the natural shoulder. The observed rate of functional decline was found to be independent of age, sex, and preoperative diagnosis.

Reliability of hip range of motion measurement among experienced arthroscopic hip preservation surgeons

The aim of this study was to determine (i) the reliability of hip range of motion measurement among experienced arthroscopic hip preservation surgeons and (ii) the magnitude of hip flexion change with posterior pelvic tilt. Five experienced arthroscopic hip preservation surgeons (5–18 years of hip surgery experience) performed passive hip range of motion (internal and external rotation), flexion (contralateral hip extended) and flexion with posterior pelvic tilt (contralateral hip maximally flexed) on five young healthy asymptomatic volunteers (three males, two females; 34.4 ± 10.7 years of age). Motion was measured via digital photography and goniometry. Inter-observer reliability was calculated via two-way mixed, single measures, intra-class correlation coefficient. Paired t-test was utilized to compare hip flexion (with contralateral hip extended) to hip flexion with posterior pelvic tilt (with contralateral hip in forced flexion). The reliabilities of measurements of hip flexion with posterior pelvic tilt and external rotation were excellent, that of hip flexion was fair, and that of hip internal rotation was poor. The magnitude of hip flexion increase with posterior pelvic tilt was 17.0° ± 3.0° (P < 0.001). The reliability of hip range of motion measurement by five experienced arthroscopic hip preservation surgeons was excellent for measures of hip flexion with posterior pelvic tilt and external rotation. Contralateral maximal hip flexion significantly increased ipsilateral hip flexion (approximately 17°).

Level of Evidence: Diagnostic, level III (without consistently applied reference standard)