Personal Motion Sensor Directed Rehabilitation After Lower Limb Reconstruction – A New Standard Of Care

Background

Open tibial fractures are managed in a variety of ways, but current practice fails to objectively assess short and long-term outcomes.  Not only does this limit the scope for evaluation of management strategies, but it also prevents the provision of regular patient feedback and implementation of adaptive personalised rehabilitation programmes.  As a result, total recovery time, and the extent of functional recovery are likely to be suboptimal, with consequential poor rates of return to work.

Advances in miniaturised, wireless sensor technology allows resource-sparing, pervasive data capture of multiple patient features in a non-specialised environment.  Our aim was to develop and validate a robust, objective assessment method using a novel motion sensing system worn by the patient for use in both clinical and community settings (Hamlyn instrumented Functional Mobility Assessment – HiFMA).

Methods

We implemented a lightweight (7.4g) ear-worn accelerometer (e-AR sensor, Imperial College London) and tablet interface into a short activity protocol made up of tasks previously validated to assess different aspects of functional mobility.  Twenty 3-month post-open tibial fracture patients and 10 healthy subjects completed the protocol, as well as a short-form health survey (SF-36) for comparison.  Subjects' performances were rated through extraction of multiple kinematic features from the accelerometer data; techniques previously validated using high-speed cameras and a force plate-instrumented treadmill (1).  A psychometric evaluation was conducted to ascertain the reliability and validity of the HiFMA tool.

Results

The HiFMA demonstrated excellent reliability (Intraclass Correlation Coefficient > 0.90, p< 0.001) and internal consistency (Cronbach's Alpha = 0.94).  Concurrent validity was demonstrated by correlation between HiFMA and SF-36 scores (Spearman's Rho = 0.668, p = 0.005).  Significant differences in HiFMA scores between healthy subjects and patients, sub-grouped according to Gustilo-Anderson fracture classification (KW-ANOVA, X² = 18.6, p< 0.001) were shown.

Conclusions

The HiFMA shows satisfactory reliability and validity to be considered for implementation into routine follow-up of patients with open tibial fractures.  This will improve our ability to objectively profile and compare a wide variety of patient outcomes, whilst creating a platform for remote patient surveillance and early detection of complications.  Furthermore, the methods described provide a real opportunity to revamp the recovery paradigm through dynamic, self-directed rehabilitation, with huge potential for positive impact in the cost and care quality of everyday clinical services.