Background: Stress shielding in the proximal femur is a widely recognized sequel of total hip replacement. It is due to a discrepancy in the stiffness between the implant and the proximal femur. The strain characteristics of implants of differing materials on the femur have previously been demonstrated in the laboratory using strain gauges and photo-elastic techniques. These are however relatively crude techniques giving limited results. Finite element analysis has also been used, but this provides only a theoretical analysis. Digital Image Correlation is an extremely accurate technique for strain analysis previously used in micro and nano engineering research.

Methods: A stainless steel, a titanium, and a carbonfibre reinforced plastic (CFRP) femoral prosthesis of the same dimensions, were implanted without cement into 5 prosthetic femora. A 1kN load was applied using a compression device. The process was repeated with 5 other prosthetic control femora. Digital Image Correlation was used to give an extremely detailed 2D strain map of inner cortex of the proximal femora during laboratory simulated static physiological loading conditions.

Results: All implants caused stress shielding in the proximal calcar area. In Gruen zones 6–4, both the stainless steel and titanium implants caused statistically significant stress shielding, whereas the femora implanted with the CFRP prosthesis did not show a statistically different strain pattern from the control group. There was a reduction in strain experienced by the medial cortex of the femora beyond the tip of all of the implants.

Conclusion: Digital Image Correlation is a novel method for strain measurement within Orthopaedic research which produces extremely accurate strain maps and data that can be reliably used for statistical analysis. Using this technique, this laboratory based investigation indicates that a carbon-fibre reinforced plastic stem is a good candidate to avoid stress shielding in total hip replacement surgery.

Systems for collecting information about patient care are increasingly common in orthopaedic practice. Databases can allow various comparisons to be made over time. Significant decisions regarding service delivery and clinical practice may be made based on their results.

We set out to determine the number of cases needed for comparison of Thirty-day mortality, inpatient wound infection rates and mean hospital length of stay, with a power of 80% for the demonstration of an effect at a significance level of p< 0.05. We analysed two years of prospectively collected data on 1,050 hip fracture patients admitted to a city teaching hospital. Power calculations were performed using standard equations from the literature.

Detection of a 10% difference in 30 day mortality would require 14,065 patients in each arm of any comparison, demonstration of a 50% difference would require 643 patients in each arm; For wound infections, demonstration of a 10% difference in incidence would require 23,921 patients in each arm and 1127 patients for demonstration of a 50% difference; For length of stay, a difference of 10% would require 1,479 patients and 6660 patients for a 50% difference.

Our data helps to illustrate the importance of sample size when interpreting the results of performance monitoring. Since a unit as large as our own only admits 525 patients per year, comparisons between trusts would require very prolonged data collection. Within a single unit the demonstration of poor performance by one surgeon or one team would clearly be impossible. Statistically meaningful analyses will only be possible with major multi-centre collaborations, as will be possible if hospital Trusts participate in the National Hip Fracture Database.

We implanted titanium and carbon fibre-reinforced plastic (CFRP) femoral prostheses of the same dimensions into five prosthetic femora. An abductor jig was attached and a 1 kN load applied. This was repeated with five control femora. Digital image correlation was used to give a detailed two-dimensional strain map of the medial cortex of the proximal femur. Both implants caused stress shielding around the calcar. Distally, the titanium implant showed stress shielding, whereas the CFRP prosthesis did not produce a strain pattern which was statistically different from the controls. There was a reduction in strain beyond the tip of both the implants.

This investigation indicates that use of the CFRP stem should avoid stress shielding in total hip replacement.

Introduction: Trochanteric bursitis is a common hip problem that can be refractory to treatment. The available modalities of treatment can be less effective. We evaluated the use of extra-corporeal shockwave therapy treatment for trochanteric bursitis.

Methodology: 22 patients with the clinical and radiological (in 6 patients) diagnosis of trochanteric bursitis were treated in a dedicated shockwave therapy clinic using Swiss dolocast radial shockwave therapy machine. 3 sessions of treatment were given one week apart, delivering 2000 impulses at 10 Hz at each session. Patients were evaluated prior to treatment, 3 months, 6 months and 12 months following their treatment. The visual analogue score (VAS) was used in all patients pre and post treatment. Hip disability and osteoarthritis score (HOOS) was performed post-treatment.

Results: Between December 2005 and November 2008 22 patients were treated for symptoms of trochanteric bursitis. There were 17 women and 5 men. The average age was 55.8 years (range 33–76 years). 6 patients had proven increase signal on MRI scan the rest were mainly clinical diagnosis and after a limited response to steroid injections. Their VAS improved from 10 to 5. Their post-treatment HOOS score averaged 255.

Of the 6 patients who had MRI proven increased signal 5 patients had significant improvement. The average improvement in the VAS was 10 to 2.3 and their HOOS scores were 349.2 (range 427–243).

Conclusion: Though the number of patients in this study is only 22 it seems that radial shockwave therapy treatment for trochanteric bursitis is promising, especially on those who have got high signal on MRI scans.

Purpose of study: ALL is the commonest childhood malignancy and current survival rates reach 80%. Consequently adverse effects of therapy may have significant long-term implications. Treatment is risk stratified with the higher intensity regimens B and C receiving more Dexamethasone and Methotrexate, both of which are known to have significant bony effects. The skeletal morbidity associated with ALL and its treatment, particularly AVN, is being increasingly identified. AVN is rare in paediatric practice. Its pathophysiology is largely unknown, although it is probably related to corticosteroid use.

Method: The records of a series of 7 out of 53 children treated with chemotherapy for ALL as per MRC ALL 99/01 and ALL 2003 protocols in a single tertiary paediatric oncology centre were reviewed. All 7 cases (3 male) had MRI confirmation of AVN (2 normal x-rays). All cases had been treated on higher intensity chemotherapy regimens and were at least 6 months from commencement of anti-leukaemic therapy. All presented with transient limb pain.

Results: The AVN was multi-focal (median 4 sites) and was associated with significant other bony abnormalities, including joint collapse, fracture, osteomyelitis and septic arthritis. In this series the dose of steroids did not correlate with the severity of the AVN. Treatment options were limited with all cases receiving conservative treatment

Conclusions: Careful consideration must precede a recommendation to stop steroids as this may compromise leukaemic cure. Although the long-term consequences of AVN on bone health are unknown, we recommend a high index of suspicion in professionals who are treating these children to ensure prompt diagnosis.

Purpose of study: The UMEX frame was developed from the Joshi external fixator, being first used in the UK in 2004. It corrects deformity by gradual distraction and manipulation. We report the outcomes of a two centre combined experience of the UMEX frame for the treatment of complex congenital foot deformities.

Method: The frame was used in the management of 27 complex foot disorders, the majority of which were resistant club feet. All patients had at least 18 month follow up.

Results: Good deformity correction was achieved in all cases, with a plantigrade foot immediately post-treatment. However, minor degrees of relapse have been noted when the strict postoperative regimen was not followed.

Conclusions: The application of external fixators for the correction of foot deformities can be a complex procedure for the surgeon, and cumbersome for the patient. This frame is simple to apply and manage and allows multi-planar deformity correction in one stage. Our experience and patient outcome data suggest that this technique is a useful surgical option for the Paediatric Orthopaedic surgeon dealing with a relapsed club foot and other complex foot deformities.

In a prospective study to evaluate the benefits of radial extracorporeal shockwave therapy (ESWT) in patients with longstanding chronic Achilles tendonitis. 34 cases of non-insertional Achilles tendonitis were treated in 32 patients, using radial shockwave treatment. Symptoms had been present for at least ten months and were resistant to conservative treatments. Patients received three shockwave sessions at weekly intervals. Evaluation was performed prior to treatment, at six weeks and three months after the final session. Patients completed a visual analogue score (VAS) for maximal pain (0–100), the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot Scale and the Victorian Institute of Sport Assessment-Achilles questionnaire (VISA-A).

At short-term review all patients reported an improvement in symptoms. The VAS fell from a pre-treatment value of 74 (+/−15) to 22 (+/−17). An improvement in the AOFAS from of 64 (+/−10) to a post-treatment value of 90(+/−7) was seen, and an average from 30 to 70 in the VISA-A score. No complications from the treatment were reported. Four patients previously listed for surgery have improved sufficiently to be removed from the waiting list.

Conclusion: Short-term results using ESWT for the treatment of longstanding non-insertional Achilles tendonitis are encouraging. Longer-term follow-up subsequent to this prospective pilot study is underway to assess if results are reproducible over a greater time period.

Introduction Pan-talar nailing for ankle arthrodesis has been advocated as a salvage procedure for post-traumatic arthrosis and Charcot’s joint. This study evaluates the outcome of pan-talar nails over a 4-year period.

Method This is a retrospective study of 11 patients (13 ankles) who underwent pan-talar nailing between 2000 and 2004. Various factors including patient demographics, indications for surgery, operation details, complications, time to fusion and need for re-operation were recorded. Nine were reviewed at a mean follow-up of 22 months for clinical and radiological assessment; two patients had died. American Orthopaedic Foot and Ankle (AOFAS) hindfoot and SF-36 scoring systems were also used for evaluation.

Results There were seven males and four females, with a mean age of 57 and 71 years, respectively. Eight patients had a pre-operative diagnosis of Charcot’s joint, one avascular necrosis of talus, one fixed deformity with polio, and one following fracture non-union.

All 13 nails were locked at both ends. The average duration of operation was 2 hours and tourniquet time 1 hour 8 minutes. All patients were kept non-weight bearing in cast post-operatively for an average of 6 weeks.

There were two cases of wound infection, one pulmonary embolism and one calcaneal fracture with infected non-union, which was treated with external fixation. There were no cases of nerve damage or septic arthritis.

All nine patients were satisfied with the operation outcome at follow-up with a mean fusion duration of 28 weeks and an average AOFAS score of 75.

Conclusion We conclude from this study that pan-talar nailing when performed for ankle arthrodesis as a salvage procedure produces a high rate of fusion with fewer complications.

The Cincinnati incision is widely utilized in clubfoot surgery and allows excellent access to the medial, lateral and posterior structures involved. Closure of the skin at the end of the procedure without undue tension may be difficult. Wound necrosis and excessive scarring may occur and may lead to inadequate correction. One alternative is to splint the foot in an initial equines position post-operatively with repeat cast changes to achieve optimal position once soft tissue swelling has decreased. A further method is to leave the wound open and allow it to granulate.

The healing and final cosmetic appearance of wounds allowed to heal by granulation following the Cincinnati incision were reviewed.

We reviewed 14 feet in 10 patients who had undergone partial closure of the Cincinnati incision following peritalar release. The majority of the children were male and the average age at surgery was 28 weeks. All corrections were performed as primary procedures on patients with idiopathic CTEV. At the end of the procedure an above-knee plaster was applied. The plaster was changed weekly in the outpatients department until the wound had healed. Patients were maintained in plaster for 12 weeks.

All final wounds were cosmetically acceptable both to the surgeon and the parents. The widest scar was 3 mm and the average time to heal four weeks. No infection had occurred although two wounds were treated for overgranulation.

Partial wound closure of the Cincinnati incision avoids undue tissue tension and allows a fully corrected position of the foot to be maintained at the end of the initial procedure. A second anaesthetic to obtain further correction is therefore avoided. Partial wound closure leaves cosmetically acceptable scarring with minimal complications. Parents should be warned about the initial appearance of the wound but may be reassured regarding final outcome.

Interbody fusion is increasingly widely used as a treatment for intervertebral disc disorders, but the biomechanics of the procedure are not well understood. The compressive loads through the spine are largely carried by the implant or bone graft, which typically rests on a relatively small area of the vertebral body. As the compressive strength of the bone is very low, subsidence of the implants into the vertebral bodies is a common clinical complication.

Previous biomechanical studies of spinal fusion have concentrated on the stiffness of the constructs, which is important in promoting fusion. Preliminary studies have shown that there are large differences in compressive strength between different implant systems, and gave an insight into the biomechanical factors that are important in determining the strength of spinal fusion constructs. This paper reports part of a larger on going study comparing anterior and posterior fusion systems, with various methods of fixation.

A major problem in interpreting the results of these tests is to distinguish between initial settling of the implants and the onset of failure to construct. We have developed a novel technique using acoustic emission monitoring to detect microcracking in the bones, which allows the onset of failure to be distinguished from initial bedding in of the implants.

Two implant systems were tested, the Syncage and the Contact fusion cage. The cages were implanted into porcine lumbar spines at L4-L5, and the implanted motion segment was then dissected out. Steel plates were mounted on each end using bone cement to ensure an even distribution of load through the vertebral body. The complete constructs were then loaded in compression, using acoustic emission sensors to detect microcracking in the bones. The load was cyclically increased in o.5kN steps until failure occurred.

The acoustic emission technique gave a sensitive indication of the onset of damage in the bones and allowed the initial settling of the implant under load to be identified. Using cyclic unloading and reloading, it was possible to accurately identify whether this damage had weakened the construct or increased its strength by redistributing stress concentrations. Initial results indicate that the Contact fusion cage fails at a much lower load than the Syncage in this model; this is ascribed to the very small contact areas between the cage and the vertebral body, which results in high compressive stresses in the bone. Under large compressive loads it appears that the constructs become unstable, and fail by buckling and plastic collapse of the vertebral bodies. Various failure models are therefore possible depending on which part of the vertebral body starts to collapse first.

In the last six months 6 cases of subacute epiphyseal osteomyelitis have presented to the Paediatric Orthopaedic Department at the University Hospital of Wales, Cardiff. We present a clinical review of these cases illustrating the salient points in their varied presentation and management, together with the results of a retrospective analysis of the incidence of this rare condition. We ask “is there an increasing incidence of this rare condition or have we become increasingly aware of this potential diagnosis in children?”