Sclerostin is a negative regulator of osteoblast differentiation and bone formation, probably through inhibition of the Wnt pathway. Distraction osteogenesis (DO) can be complicated by osteopenia and poor anabolic response, which may benefit from anabolic therapy. Sclerostin antibody (Scl-Ab) has been reported to stimulate bone formation and restore bone mass and strength in aged ovariectomised rats as well as to enhance fracture healing. We sought to examine the effects of Scl-Ab in a rat model of DO.

A femoral osteotomy was stabilised with an EBI fixator in male Sprague Dawley rats, with distraction of 0.25mm twice daily to a total 7mm. Saline or Scl-Ab was administered twice weekly throughout distraction and/or up to 4 or 6 weeks post-commencement of distraction. Three groups were examined, Saline, Delayed Scl-Ab (D Scl-Ab, post distraction only) and Continuous Scl-Ab (Cont Scl-Ab).

Radiographs demonstrated a trend for increased union rates with Scl-Ab at 6 weeks, with 50% of animals for D Scl-Ab or Cont Scl-Ab versus 20% of control animals. DEXA scans at 2 weeks revealed a 63% increase in regenerate BMD in the Cont Scl-Ab group (p< 0.01) and a 41% increase in the D Scl-Ab group (p< 0.05), compared to Saline. In addition, an increase of 116% in BMC was seen in the Cont Scl-Ab group (p< 0.01). At 6 weeks regenerate bone area was increased 18% in D Scl-Ab and 23% in Cont Scl-Ab. μCT scans of the regenerate revealed an 85%-89% increase in bone volume with Scl-Ab treatment at 6 weeks (p< 0.05). Bone volume ratio (BV/TV) was increased 77%-82% (p< 0.05).

Scl-Ab treatment enhanced the amount of bone formed in this distraction model, when given throughout or post-distraction. Histological assessment of dynamic bone formation parameters will reveal the mechanism behind the enhanced repair, and its mechanical consequences will be examined.

Glenoid loosening is a major problem in total shoulder arthroplasty. Failure of osteointegration, osteolysis and loosening are potential problems with concerning reports of these complications with earlier metal back designs. CT scans have been reported as more accurate than plain x-rays in examining fixation of components. This study examines the medium term osteointegration of the SMR (Lima) metal back glenoid component. 20 consecutive patients operated on by the same surgeon (KM) were evaluated at a mean of 3 years 9 months (range 3-5 years) using CT analysis. Films were read by a musculoskeletal radiologist (AS). 8 zones were described and the interface graded as ‘osteointergrated’, ‘lucent zone < 1mm’, ‘lucent zone 1-2mm’, ‘lucent zone > 2mm osteolysis’. Loosening was defined as lucent line on all zones > 1mm or migration of implant.

No components were loose. All components were osteointegrated around the central peg. Osteointegration was observed in 85% of zones. 4% of the zones were graded as osteolysis, all in the one patient. This patient had osteolysis 4 years post-surgery with superior subluxation of the humeral head and polyethlylene and metal wear. The glenoid component was not loose at revision surgery. Problems with this technique of assessment include radiation exposure and artefact. Small lucent zones often had a well contoured margin suggesting that the component did not seat perfectly on the bone surface in these areas.

These results confirm that reliable medium term osteointegration does occur with the SMR metal back glenoid in anatomical total shoulder replacement. Osteolysis can occur and longer term follow up is ongoing.

The glenoid is the ‘weak link’ in total shoulder arthroplasty. Concerns exist over loosening of all glenoid components. Metal back glenoid components have, in some reports, had early problems with liner dissociation, polyethylene wear, osteolysis and component fracture. In November 2003 the first metal back SMR total shoulder replacement was implanted in New Zealand (NZ). We reviewed the NZ joint registry information on anatomical total shoulder replacements over a 5-year period from the end of 2003.

There were 192 metal back SMR prostheses (Lima) implanted and 484 cemented prostheses (all brands). 70% of patients in each group completed an Oxford score at 6 months. The mean score in both groups was 40.39. There was no statistically significant difference in the revision rate in this period for revisions of any kind (p=0.07). 6/192 metal back cases had a revision procedure, but none were for the glenoid component. 7/484 cemented cases had a revision procedure with 3 being for glenoid loosening. None of the metal back glenoids were revised in this period. 5 of the cemented glenoids were revised in this period. There was a higher revision rate for instability in the metal back group with 5 in the metal back group and 2 in the cemented group being revised for instability (p=0.01). In the metal back group there were 3 revisions to a reverse shoulder arthroplasty without removal of the metal back glenoid base plate.

We have not identified an early cause for concern with the use of the metal back SMR prosthesis in anatomical total shoulder replacement in New Zealand. It is possible, but not proven, that the modularity of the implant may lower the revision threshold for some cases. Reassuringly, there were no revisions of the metal back glenoid in this early period

Purpose

In recent years, it has become increasingly common to publish the level of evidence of orthopaedic research in journal publications. Our primary research question is: is there an improvement in the levels of evidence of articles published in paediatric orthopaedic journals over time? In addition, what is the current status of levels of evidence in paediatric orthopaedic journals?

Introduction

Despite evidence of long term survival of cemented femoral stem prostheses, studies have shown concerns in the longevity of the cemented sockets. This has led to a rise in the use of uncemented and hybrid implants (with uncemented cup and cemented stem) without long term studies to determine evidence for their use. We aimed to assess whether there is any difference in clinical outcome between cemented and non-cemented acetabular fixation in elderly patients.