Clinical and biomechanical comparison between arthrodesis and total joint arthroplasty of the 1 st metatarsophalangeal joint for the treatment of hallux rigidus

Osteoarthritis of the 1st metatarsophalangeal joint known as hallux rigidus has a significant impact on quality of life and gait pattern. Numerous treatments are available for early stage hallux rigidus whilst end stage hallux rigidus is normally treated surgically after failure of conservative treatment. The two main surgical options currently offered are arthrodesis and arthroplasty. Although research has been published on arthrodesis and arthroplasty, these studies have tended to focus on clinical outcome and patient reported outcome measures. Research which has examined biomechanics are heterogenous and report inconsistent findings. Many differing methods of arthrodesis or arthroplasty are combined with research focussing on distribution of plantar pressure. Although kinematic analysis exists, only a few studies have been conducted using a multi-segment foot model and 3D biomechanics. Therefore, the aim of this programme of research was to examine biomechanical and patient reported outcome differences between arthrodesis and total joint arthroplasty using detailed spatio-temporal, kinematic and pressure analysis together with quality of life for the latest generation of total joint arthroplasty and arthrodesis. In order to set up this research, the reliability of the data obtained from the Clinical Movement Analysis Society approved gait laboratory at The University Hospitals of Burton and Derby was assessed. A detailed investigation then followed to assess changes following total joint arthroplasty (Chapter 4) and arthrodesis (Chapter 5). Finally, in Chapter 6 a comparison was made of the post-operative results following these two surgical techniques. In addition, statistical parametric mapping was employed in the kinematic comparisons to determine where in the continuous gait cycle any significant changes took place. This research found that quality of life and spatio-temporal parameters improved with both these surgical techniques most likely attributed to a reduction of symptoms. Analysis of plantar pressure demonstrated a medialisation of load following both surgical techniques however it was more pronounced following arthroplasty. This is most likely a result of sagittal iii plane forefoot hallux motion being maintained following this technique which also allowed for other positive adaptations at the hindfoot forefoot and tibia hindfoot. Only total joint arthroplasty was able to restore foot pressures and kinematics towards a more normal physiological healthy foot pattern. These findings were clinically significant and meaningful. The implications from these findings are that arthrodesis led to a compromised gait which would affect the more proximal joints negatively compared to total joint arthroplasty which resulted in a more normal pressure distribution and biomechanics. This research would recommend total joint arthroplasty in favour of arthrodesis for the treatment of end stage hallux rigidus.