Does an augmented video based portable system have a place in orthopaedics and sports injury rehabilitation?

INTRODUCTION
A new low cost Augmented Video Based Portable System (AVPS) has been designed and developed for gait assessment. This modification builds on an earlier system developed by Prof James C Wall and applied by Prof Philip Rowe. The AVPS has been concurrently validated against a gold standard 3D motion analysis system as a useful potential rehabilitation assessment tool with applications within the clinical setting. Previous research has validated the AVPS using healthy participants and stroke patients. To date the AVPS is yet to be used within the field of orthopaedics and sports injury rehabilitation. The Achilles Tendon Rupture (ATR) has been chosen as the preferred musculoskeletal injury to be investigated primarily because it is common and said to be on the rise. It is the strongest tendon in the human body with an incidence rate of 18-37 per 100,000. Typically, it has been shown to tear or rupture in middle-aged males in their 30s and 40s who play sport intermittently. As an application within orthopaedics and sports injury rehabilitation, this planned study aims to use the AVPS as an optimum tool, to evaluate the process of recovery and rehabilitation of an ATR patient.

METHODS
One adult male patient aged 25 years old with a mass of 86kg and height of 1.83m participated in the study. A case study was designed to evaluate a prescribed physiotherapy program on a non-surgical complete Achilles tendon rupture rehabilitation patient using temporal-spatial parameters as the outcome measure. The patient underwent conservative treatment to repair an ATR on his left limb. The study took place at the Biomechanics Laboratory located at the University of The West of Scotland. Data was collected from the onset of the rehabilitation process right through to the follow up sessions after baseline measurements were obtained. The study monitored the patient throughout are habilitation process of prescribed exercise administered by a qualified physiotherapy practitioner. The prescribed physiotherapy intervention was based on the conventional physiotherapy routinely administered to ATR patients within the National Health Service. The gait assessment required the patient to walk wearing comfortable shoes across a 6m long, high-contrast-grid vinyl mat while being video-filmed in the sagittal plane. Bi-directional temporospatial gait analysis and the production of sagittal plane estimates of joint kinematics were measured using the Silicon Coach Software (Dunedin, New Zealand). Bull’s eye markers were placed on the hip joint, knee joint, ankle joint, heel and toe. The assessment sessions were carried out at four time points (TP) during the recovery period. TP1 was the baseline measurement which was performed after the cast removal and prior to starting physiotherapy. TP2 was performed during the first week of physiotherapy and three weeks from baseline. TP3 and TP4 were carried out at nine weeks and seventeen weeks from baseline respectively. Descriptive statistics were applied. Paired t-tests were carried out to compare time point 1 (TP1) with each subsequent time point i.e. TP2, TP3 and TP4. The left limb temporo-spatial gait parameters were compared with the control limb as a means to biomechanically evaluate the level of recovery. Gait symmetry was also measured for walking speed, step time and step length and expressed as a ratio of the affected limb to the healthy limb.

RESULTS AND DISCUSSION
The gait speed, temporal and spatial parameters produced symmetries closer to 1 at TP4 when compared to TP1. Both the left and right limb knee joint angles at initial contact showed no significant differences between TP1 and the other time points (p > 0.067). However, there were significant differences in the knee joint angles between time points TP2 and TP3 for the left limb (p = 0.038), and TP3and TP4 for the right limb (p = 0.008). For the left limb, at terminal contact, there were significant differences between the knee joint angle baseline measurement and TP2 and TP3(p < 0.010) respectively. No significant differences were observed between TP1 and TP4 (p = 0.067). Both the left and right walking speeds showed significant differences between TP1 and all other time points (p < 0.009). The step length (p < 0.02) and step time (p < 0.015) showed significant differences between TP1 and all other time points. Throughout the gait assessment at the four different time points both limbs showed significant differences in their step lengths (p < 0.006). Also, apart from TP1 knee joint angle at terminal contact (p = 0.04), TP1 walking speed(p = 0.001) and TP1 step time (p = 0.017), all other measurement parameters TP2, TP3 and TP4 showed insignificant differences between the left and right limbs(p > 0.109). The results of the temporo-spatial parameters at TP4 are in agreement with previously published work on healthy participants.

CONCLUSIONS
Although the temporo-spatial parameters seem to have provided useful outcome measures, the level of sensitivity of the measurement parameters in response to the patient’s rate of recovery appeared consistently more pronounced in the walking speed, step length and gait symmetry measurements.