Physiological morbidity associated with hip fracture.

Abstract

Fractured neck of femur not only causes considerable mortality 1, but also significant reduction in physiological functioning in the weeks and months after injury. We illustrate this point with the case of a fit, 43-year-old, non-elite cyclist, who suffered a fractured neck of femur after a cycling accident. Cardiopulmonary exercise testing (CPET) data from a previous study (Table 1) were available as a baseline measure, before the injury. The fracture required fixation with a dynamic hip screw performed under general anaesthesia. The subject had an uncomplicated postoperative recovery and was able to weight bear within 24 hours. He restarted exercising on a static bicycle after two weeks, followed by a graded intensive rehabilitation; CPET data were collected again at 8, 12 and 36 weeks, using the Zan 600 cycle ergometer exercise-testing suite (Nspire Health Ltd, Hertford, UK) with anaerobic threshold determined electronically by the V-slope method. o2 at anaerobic threshold; ml.kg−1.min−1 Haemoglobin concentration was reduced on the first postoperative day (100 g.l−1) but had returned to normal (135 g.l−1) by four weeks and remained at this level at 12 weeks. We believe this case will be of interest to readers as it demonstrates a case in which post-injury exercise data can be compared with pre-injury baseline data in traumatic injury. At eight weeks post-injury, the oxygen uptake (o2) was 25% lower, and the anaerobic threshold (AT) was 10% lower. We think it is unlikely that a decreased haematocrit (and oxygen carrying capacity) contributed to these results, as the haemoglobin concentration had returned to normal at four weeks. By 12 weeks, o2max had returned to baseline, with an AT above baseline value. Repeat testing at 36 weeks was unchanged. Our subject was highly motivated to regain pre-injury fitness levels, and despite this, return to baseline values still took eight weeks. Less motivated patients may not be able to attain this level of rehabilitation without help. Rehabilitation programmes have been shown to enhance quality of life and reduce mortality in other diseases 2. The results from these studies suggest that rehabilitation programmes should specifically target improvements in muscle mass and strength as well as general cardiorespiratory fitness. More work needs to be done to look at this in greater detail, as it may be that rehabilitation programmes need to be tailored far more to individual needs than previously recognised.