Advances in algorithms developed with sensor data from smart phones demonstrates the capacity to passively collect qualitative gait metrics. The purpose of this feasibility study was to assess the recovery of these metrics following joint reconstruction. A secondary data analysis of an ethics approved global, multicenter, prospective longitudinal study evaluating gait quality data before and after primary total knee arthroplasty (TKA, n=476), partial knee arthroplasty (PKA, n=139), and total hip arthroplasty (THA, n=395). A minimum 24 week follow-up was required (mean 45±12, range 24 - 78). Gait bouts and gait quality metrics (walking speed, step length, timing asymmetry, and double support percentage) were collected from a standardized smartphone operating system. Pre- and post-operative values were compared using paired-samples t-tests (p<0.05).

A total of 595 females and 415 males with a mean age of 61.9±9.3 years and mean BMI of 30.2±6.1 kg/m² were reviewed. Walking speeds were lowest at post-operative week two (all, p<.001). Speeds exceeded pre-operative means consistently by week 21 (p=0.015) for PKA, and week 13 (p=0.007) for THA. The average weekly step length was lowest in post-operative week two (all, p<0.001). PKA and THA cases achieved pre-operative step lengths by week seven (p=0.064) and week 9 (p=0.081), respectively. The average weekly gait asymmetry peaked at week two post-operatively (all, p <0.001). Return to pre-operative baseline asymmetry was achieved by week 11 (p=0.371) for TKA, week six (p=0.541) for PKA, and week eight (p=.886) for THA. Double limb support percentages peaked at week two (all, p<0.001) and returned to pre-operative levels by week 24 (p=0.089) for TKA, week 12 (p=0.156) for PKA, and week 10 (p=0.143) for THA.

Monitoring gait quality in real-world settings following joint reconstruction using smartphones is feasible, and may provide the advantage of removing the Hawthorne effect related to typical gait assessments and in-clinic observations.

We sought to evaluate the early post-operative active range-of-motion (AROM) between robotic-assisted total knee arthroplasty (raTKA) and conventional TKA (cTKA). A secondary data analysis on a global prospective cohort study was performed. A propensity score method was used to select a matched control of cTKA from the same database using 1:1 ratio, based on age, sex, BMI, and comorbidity index. This resulted in 216 raTKA and cTKA matched cases. Multivariable longitudinal regression was used to evaluate difference in ROM over time and values are reported as least squares means (95% confidence interval). The longitudinal model tested the treatment effect (raTKA vs cTKA), time effect, and their interaction with control on covariance of patients ‘s age, sex, BMI, comorbidity and pre-operative flexion. Logistic regression was used to analyze the active flexion level at one month (cut by 90°) and three months (cut by 110°).

At one-month postoperative the raTKA cases had more AROM for flexion by an average of 5.54 degrees (p<0.001). There was no difference at three months (p=0.228). The raTKA group had a greater improvement from pre-operative values at both one-month, with an average 7.07° (3.6°, 10.5°, p<0.001) more improvement, and at three-months with an average improvement of 4° more (1.61°, 7.24°, p=0.0115). AROM for extension was lower overall in the raTKA group by an average of 0.44° (p=0.029). The raTKA patients had higher odds of achieving ≥90° of flexion at one-month (OR 2.15, 95% CI 1.16, 3.99).

raTKA resulted in greater AROM flexion gains in the early postoperative period than cTKA. Additional research is needed to understand if these earlier gains in AROM are associated with improved patient satisfaction and continued improvements with time.