The ankle and hindfoot

The factors to measure in assessing outcome of the ankle and hindfoot comprise either signs, symptoms, complications or investigations (Pynsent 2001), and these are most often variously combined within a scoring system. ‘Signs’ by definition are objective, and these most commonly encompass ranges of movement, quantification of deformity and stability. Although historically there has been a tendency towards placing more credence in these objective criteria, this approach is changing as it is becoming fairly well recognized that the measurement of some objective criteria are open to significant error (Dawson and Carr 2001) and the measures themselves may be non-validated and poorly reproducible (Drake et al. 1994; Conboy et al. 1996). There is little doubt that both the range of movement and alignment at the ankle and hindfoot may be affected by both pathology and treatment. The exact relationship of this to function and correlation with outcome is however less well defined. If these are assessed it is important to define the reference landmarks for clinical measurements of movement or deformity, as this may significantly effect the results (Bohannon et al. 1989), though this is almost universally ignored. The singular lack of inter-observer agreement in clinical measurements at both ankle and subtalar joints is documented (Elveru et al. 1988), though intraobserver agreement can be within acceptable limits, as can radiographic measurement of movement (Backer and Kofoed 1989). Clinical measurements of ankle and subtalar movement, once made, should probably be compared with a contralateral normal side – if this exists – given the recognized wide

variation in documented normal ranges (Oatis 1988). In addition, it has been demonstrated that the clinical measurement of subtalar movement is poorly reproducible (Leicht and Kofoed 1992). Despite these well-recognized sources of error, most of the scoring systems in usage avoid addressing these issues all together. It is increasingly appreciated that a patient’s subjective assessment of outcome such as pain, functional ability and satisfaction may fulfil the criteria of being valid, reliable and sensitive to change if gathered by a correctly designed and tested patient-centred questionnaire (Dawson and Carr 2001). The WOMAC score for osteoarthritis of the hip and knee is one such instrument (Bellamy et al. 1988), but there exists no comparable fully validated diseasespecific measure for the ankle and hindfoot. The Foot Function Index (Budiman-Mak et al. 1991) is the only fully validated regional scoring system, but this has only been used in a rheumatoid arthritis population, excluding operated cases and those with fixed deformities. It has however seen wider usage (Skalley et al. 1994; Coester et al. 2001) which should be regarded with some caution. There has been a move towards the use of patient-based generic scores of health, in particular the SF-36 (Ware and Sherbourne 1992), in conjunction with more traditional outcome scores of ankle and hindfoot. Generally, its elements have been used either as a yardstick against which to regard a non-validated score (Heffernan et al. 2000), or to provide a more holistic view of the patient’s response to intervention (Egol et al. 2000).