Statement of purpose

We review the current state of development of proton therapy and the implications for beam therapy in the management of primary bone tumours

Bearing diameter and acetabular component orientation have been shown to be important variables effecting blood metal ion levels following hip resurfacing arthroplasty. So far no studies on bilateral hip resurfacings have taken into account these variables.

We examined the serum ion results of patients under the care of two experienced hip resurfacing surgeons who carry out ion analysis as part of routine post operative care. Surgeon 1: Patients were implanted exclusively with a “third generation” resurfacing device. Surgeon 2: Patients were implanted with the same “third generation” device and also a low clearance “fourth generation” resurfacing device. Only ion results from patients who were 12 months post surgery were included. Bilateral patients were matched to unilateral patients according to the surgeon performing the operation; the resurfacing system implanted and cup inclination and anteversion angles. The ion data from each bilateral group was tested against the corresponding unilateral groups using the Mann Whitney U test for non parametric data. Significance was drawn at p<0.05.

Surgeon 1: There were 310 patients with unilateral joints and 50 with bilateral joints. There were no significant differences with regard to time to follow up, activity levels, joint sizes or cup orientations. Serum chromium (Cr) and cobalt (Co) concentrations were significantly greater in the bilateral group (p<0.001). Median ion levels were greater in the bilateral group by a factor of >2 in the smallest joint sizes and <2 in the largest joints. Surgeon 2: There were 11 patients with bilateral third generation resurfacing joints and 50 with unilateral joints of the same design. The same relationship as described above was identified. There was a notable difference in the fourth generation implant group (n=13 bilateral, n=100 unilateral). Median ion levels for patients receiving bilateral joints of sizes <47mm were ten times greater than in the corresponding unilateral group.

Bearing diameter and component design are critical factors in determining metal ion levels following bilateral hip resurfacings. Surgeons must consider the potential implications of gross increases in metal ion levels prior to performing bilateral hip resurfacings in smaller patients.

Introduction: Conflicting opinions exist as to whether bone healing is affected by the administration of bisphosphonates for osteoporosis. In an animal model, we assessed the effect of bisphosphonates on osteoporotic fracture healing and whether the timing of administration made a difference.

Methods: 36 female Wistar rats underwent a mid-diaphyseal femoral osteotomy six weeks after ovariectomy. They were then divided into 3 groups:

no treatment (control);

Results: Of the 36 rats, 8 were unable to complete the study. Group 3 differed from control in three respects: higher bone mineral content (BMC) and density (BMD); larger callus; lower torsional stiffness. Group 2 did not differ significantly from control. There was a significant positive correlation between stiffness and change in BMC in group 1 (r=0.85, p< 0.001) but not so for group 2 (r=0.2, p> 0.05) and group 3 (r=0.04, p> 0.05). A similar trend existed for all radiographic parameters in the three groups.

Conclusion: The results suggest that, with early bisphosphonate treatment, although there is an increase in the size of the callus, that callus is biomechanically inferior. Furthermore, administration of bisphosphonates at either stage destroys the relationship between radiographic and mechanical parameters used to assess fracture healing.

While hidden blood loss has been shown to occur in hip fractures the timing and cause have not yet been demonstrated. This study investigated the degree of pre-operative blood loss within the first 24hrs after intertrochanteric hip fracture.

188 patients with extracapsular hip fractures had their full blood count taken on admission and after 24 hours. The haemoglobin (Hb) and haematocrit (Hct) were noted at each time. Fractures were grouped as undisplaced or displaced. Those who were operated on prior to the 24hr blood sample were excluded. All patients with intracapsular or sub-trochanteric fractures were excluded, as were any who received a blood transfusion prior to their 24hr blood sample being taken. The tests for differences between blood samples and the existence of displacement were performed using paired and independent Student’s t-test. The level of significance was set at P< 0.05. All data was analysed using SPSS statistical software version 11.

The overall fall in the Hb within 24hr was significant (1.6 g/dl, P< 0.001), as was the fall in the haematocrit (0.05, P< 0.05). Displaced fractures had a significantly lower Hb at 24hrs than undisplaced (10.6g/dl vs 11.8 g/dl, P=0.001). The fall in Hb was significantly greater in displaced fractures compared to undisplaced (1.7g/dl vs 1.2g/dl, P< 0.05). Changes in the Hct mirrored those of the Hb.

This study identified a significant blood loss that occurs within the first 24hrs after an intertrochanteric hip fracture, prior to theatre. The cause is unlikely to be secondary to dehydration as the Hct fell with the Hb. Thus the most likely cause is the trauma itself. The admission Hb is possibly an inaccurate measure of the true value and patients may be more shocked than first thought. A more liberal resuscitation policy may be warranted.