Summary Statement

A population based finite element study that accounts for subject-specific morphology, density and load variations, suggests that osteoporosis does not markedly lower the mechanical compliance of the proximal femur to routine loads.

The two week wait has been established as a potential means of diagnosing malignant tumors earlier and thus hopefully leading to improvements in outcome. There remains controversy as to whether these clinic achieve this end or whether they just speed up treatment of patients already diagnosed (eg by imaging)

Aim: The aim of this study is to evaluate the diagnoses of all patient referred with a suspicious soft tissue lump to a two week wait clinic, to assess the diagnostic ‘hit rate’ and how many of these had already had imaging leading to a possible diagnosis of malignancy.

Method: Review of the diagnoses and referral criteria for all patients referred to a soft tissue sarcoma early diagnosis clinic.

Results: ** patients were referred under the 2 week wait criteria with a possible soft tissue sarcoma. ** (**%) turned out to have a malignant diagnosis. Of these, *8 were STS, ** were other soft tissue malignancies and ** were bone malignancices (** being….) Of the patients with a malignant diagnosis, only ** were referred directly to this hospital as a two week wait without previous investigation. Of the remainder *8 had undergone imag-9ing prior to referral leading to a suspicion of malignancy and ** were referred after investigation at another hospital. The average size of STS diagnosed after 2 week wait referral was ** which compared with **cm in those not referred via this route over the same time period.

Conclusion: Patients referred to a soft tissue 2 week wait clinic had a **% risk of malignancy. Of these, ** were new diagnoses suspected purely on clinical as opposed to imaging grounds.

Background: When treatment of a spinal arterio venous fistula (SAVF) is anticipated, precise location of the level and side of the feeding artery are necessary. Digital subtraction angiography (DSA) is the reference standard for imaging SAVFs. Non-invasive vascular imaging by multidetector computed tomographic angiography (MDCTA) and magnetic resonance angiography (MRA) are newer imaging modalities, which are able to demonstrate these lesions.

Objectives: We performed a retrospective analysis of patients with SAVF in our unit to examine the accuracy of MDCTA and MRA compared with DSA and intraoperative findings to illustrate how non-invasive angiography affects treatment.

Results: Between 2001 and 2007, we identified 22 consecutive patients with SAVF. 20 patients had CTA, identifying the site of SAVF in 19. In all of the 11 patients who had MDCTA, the site was correct and confirmed at surgery.

16 patients had MRA, confirming the SAVF in all cases and correct site in 12.

DSA failed to demonstrate the abnormality in one patient.

Treatment: 5 patients have had no treatment. 3 patients were treated by embolisation, with one patient developing a persistent neurological deficit. 14 patients had primary surgical repair with confirmation of the angiographic lesion. In those cases where pre-operative MDCTA was performed, volume rendered spinal reconstructions aided the operative localisation.

Conclusion: Non-invasive angiography for the diagnosis of SAVF is safe and accurate. MDCTA aids operative localisation and DSA should be reserved for patients with inconclusive non-invasive angiography or when identification of the artery of Adamkiewicz is required prior to embolisation.

The hypothesis of the current study was that the loading of the proximal femur is altered significantly by the surgical approach. The change in long-term periprosthetic bone mineral density in relation to the alteration of the musculature after the anterolateral (Group A) and transgluteal approaches (Group B) has been compared. Group A comprised 35 hip joints (30 patients) and Group B 47 hip joints (37 patients). No significant differences were seen between groups in respect to age, gender, or diaphyseal BMD distribution and in respect to average stem size in a Wilcoxon test. Measurement of BMD in femoral Gruen Zones I, II, VI, and VII revealed a significant bone loss in Group B compared with Group A; however the functional outcome showed no significant differences between the two groups postoperatively. Analysis of proximal femoral loading by means of a validated musculoskeletal model showed a considerable redistribution of the musculoskeletal loading across the hip during walking and stair climbing after a transgluteal compared with an anterolateral surgical approach. The muscular damage caused by the surgical approach seems to have a significant influence on the long-term bone loss and the initial postoperative loading of the proximal femur.

Purpose To determine which patients respond best to viscosupplementation injections for osteoarthritis of the knee.

Methods and Results We undertook a prospective study of all patients undergoing Hylan G-F 20 injections in the knee recording the indication, severity of symptoms, baseline demographic details and the WOMAC score. Outcome data was collected at 3, 6 and 12 months at an independent telephone interview to determine if patients were improved, the same or worse, and by postal WOMAC score.

100 patients were studied. 3 records were excluded, as there was no follow-up recorded. The demographics on 97 were: mean age 67 (range 37–91), male 56%, mean duration of symptoms 8.8yrs and primary OA in 65%.

Overall 43% were improved at 3 months, 31% at 6 months and 29% at 12 months. When the results were analysed according to indication, patients with ‘moderate non-mechanical osteoarthritic symptoms after failed medical management and not severe enough for arthroplasty’ did best (49% at 3 months and 38% at 6 months). Patients with ‘persisting arthritic symptoms after attempted arthroscopic debridement for mechanical type knee symptoms’ had less predictable results (42% improved at 3 months and 23% at 6 months). Patients with ‘severe or deteriorating symptoms while awaiting knee replacement’ or who were ‘too medically ill for TKR’ had a low rate of improvement (18% at 3 months).

Conclusion Viscosupplementation is unreliable in patients with end stage OA awaiting TKR. This study allows for better targeting of this useful expensive treatment modality.

Introduction: The stress and strain in the proximal femur after total hip arthroplasty are influenced by the geometry of the implant in addition to its materials properties and applied loading. The addition of a third taper in the medio-lateral plane may provide additional stability and improved load transmission.

Aim: To examine the relative stability of double and triple tapered stems in two finite element (FE) models.

Methods: The geometry of a polished, double-tapered and a triple-tapered stem were scanned using a three dimensional technique. Two FE models of the stems were created using PATRAN. The models were analysed using the ABAQUS. Tied and sliding contact conditions were allowed between the implants and the cement mantle. The interface at the distal tip of the stem was removed to represent the scenario with a distal centraliser present.

Results: When tied contact was assumed, both stems displayed similar von Mises’ stress distributions. The peak stresses remained constant in the double tapered stem, with a marked translation of regions of high stress towards the distal tip with the introduction of sliding contact conditions. Peak stresses in the triple tapered stem decreased, but displayed a more continuous distribution along the implant with sliding contact. Torsional loading of the stems reduced the magnitude of the distal tip stresses.

Conclusions: The triple-tapered geometry displayed a more even distribution of stresses along the length of the implant. The double-tapered geometry displayed a high stress state at the distal tip of the implant.