Osteoarthritis of the knee joint and hyperextension of the knee joint after stroke

Abstract

Introduction: Some physiotherapists are reluctant to allow their patients to walk on a hyperextended knee after stroke in the unproven belief that it will precipitate the development of symptomatic osteoarthritis of the knee joint.

Aims: The primary aim of this project was to determine if stroke victims who walk with a pattern characterised by hyperextension of the knee joint during the stance phase of gait are more likely to develop osteoarthritis of the knee joint (OA) than those who do not. Secondary aims were to note any changes in gait pattern since discharge from physiotherapy, and the utilisation of walking aids and splints that might have been prescribed during treatment. The incidence of first stroke in Christchurch permitted the recruitment of sufficient subjects in this study. In the early 1990's two physiotherapy approaches to the treatment of gait disturbances after stroke held sway in Christchurch. One philosophy recommended that background postural reactions be mastered before attempting to weightbear. The other philosophy recommended early teaching of specific functional activities to prevent the acquisition of secondary muscle length changes, contractures and reflex hyperactivity. Osteoarthritic changes can be found in most people over the age of 40 years. It is therefore reasonable to assume that most of the study group would have some joint changes. The imposition of chronic excessive use of end range weightbearing during gait may be sufficient to precipitate symptomatic OA knee.

Method: A case control study was designed matching stroke patients with a history of walking with a hyperextended knee after stroke to those that did not walk in this manner. Subjects who had a stroke in 1992 and 1993 were recruited from the files of Canterbury Health Ltd. These were followed up in 1998. An algorithm developed by the American Rheumatology Association was used to diagnose OA knee. Subjects were visited at their home, the algorithm was applied and an observational gait analysis was undertaken in order to determine the position of the knee joint during the stance phase of gait.

Results: A total of 734 patients were discharged from Christchurch Hospital with a diagnosis of stroke in 1992-3. However, after inclusion and exclusion criteria were applied only 84 were available for follow up. Of these 84 only 15 were available for assessment. Five patients exhibited hyperextension of the knee and ten patients did not. Osteoarthritis of the knee joint was present in three and five of these respectively. The sample size was too small for meaningful comparison but it was clear that the prevalence of OA knee was similar in both groups. Utilisation and compliance with prescribed walking aids, and changes in gait pattern over time could not be compared due to the small sample.

Discussion: Strict inclusion and exclusion criteria limited the sample and precluded any meaningful findings. Any relationship between hyperextension of the knee and OA after stroke therefore remains unproven. Difficulties in elderly research include recruitment, compliance to commands and understanding questions, which were all apparent in this project. A subsequent study has been designed taking into account the problems encountered in the initial investigation. This study will investigate the relationship between walking after stroke and the development of knee pain, and the influence of different types of physiotherapy approach on the occurrence of hyperextension of the knee joint after stroke.

Conclusion: It was not possible to demonstrate any link between walking pattern after stroke and the development of symptomatic OA knee.