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Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_II | Pages 124 - 124
1 Feb 2004
Harty J Soffe K O’Toole G Stephens M
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Plantar faciitis is a repetitive microtrauma overload injury of the attachment of the plantar fascia at the inferior aspect of the valvaneus. Several aetiological factors have been implicated in the development of plantar faciitis, however the role of hamstring tightness has not previously been assessed.

Materials and Methods: 15 volunteers (mean age 25 years) were prospectively analysed for the difference in forefoot loading using a don-Joy brace applied to each knee simultaneously. The brace was locked at varying degrees of knee flexion (0°, 20°, 40°). Body weight was measured for each volunteer. 15 patients (mean age 41 years) with a diagnosis of plantar faciitis were similarly analysed on the pedobarograph, however they also had their hamstring tightness assessed by means of measuring the popliteal angle. The mean popliteal angle measured was 28.5°. 15 age and sex matched controls (mean age 42 years) then had their hamstring tightness assessed. The mean popliteal angle was 12.5°.

Increasing the angle of flexion from 0–20° at the knee joint led to statistically significant increase in pressure in the forefoot phase by an average of 0.08K/cm2s (p, 0.05,t-test). An increase from 20 – 40° led to increased forefoot phase pressure of 0.15 kg/cm2s (p0.05, t-test). The percentage time spent in contact phase reduced from 30 to 26.5 to 16 with increasing flexion (P< 0.05). However there was an inverse increase in the time spent in the forefoot phase 51–58–69 with increasing degrees of flexion (P< 0.05). Thus the authors feel that an increase in hamstring tightness may induce prolonged fore foot loading.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_II | Pages 125 - 125
1 Feb 2004
Hurson C Synnott K Ryan M O’Connell M Soffe K Eustace S O’Byrne J
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Introduction: The Ganz periacetabular osteotomy aims to improve femoral head coverage in dysplastic hips. It is joint preserving procedure and therefore is ideally preformed before significant articular cartilage degeneration. One proposed advantage of this procedure is that it partially preserves the posterior column and does not disrupt the vascular supply of the main fragment. This study aims to 1) assess the role of MR imaging in the perioperative evaluation of articular cartilage and labrial tissues prior to Ganz osteotomies and 2) to document any alteration in the vascularity of the acetabular fragment post operatively.

Patient and Methods: Twenty patients (all female, average age 18.2 years) under consideration for peracetabular osteotomy for hip dysplasia and MR Studies of the pelvis as part of the perioperative assessment. Sixteen patients had follow-up imaging at 4, 12 and 26 weeks post surgery, at which time evidence of healing, oedema, vascularity and femoral head coverage were assessed.

Discussion: MR imaging has proven to be a reliable method of assessing articular cartilage health before considering pelvic osteotomy. Hopefully this will allow more appropriate selection of patients likely to benefit from this procedure. In addition MRI scanning allows clearer assessment of other articular elements, such as labium and ligamentum teres, that are difficult to visualize with plain radiographs and CT scans. A further benefit of MR scanning is that, as this study has shown the vast majority of patients who are potential candidates are female of childbearing age and it voids the use of ionizing radiation in this sensitive group of patients. This study has shown that despite some early alterations in osteotomy fragment vascularity the ultimate outcome is that vascularity is substantively unharmed by periacetabular osteotomy.

Conclusion: MR imaging is extremely useful in the perioperative workup and postoperative follow-up in patients undergoing Ganz periacetabular osteotomies.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_II | Pages 140 - 140
1 Feb 2003
Sheehan E Soffe K McKenna J McCormack D
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Cement is still in common usage in primary and revision arthroplasty surgery. Infection rates in cemented arthroplasties ranges from 1–4% and poses a huge problem for the revision arthroplasty surgeon. Infection in septic implants is biofilm based and almost completely resistant to conventional anti-microbial therapy. Recent papers have questioned the efficacy of using gentamicin-loaded cement in arthroplasty as staphylococcus aureus biofilms will develop on same. The focus of this study was to investigate the efficacy of antibiotic loaded cement in preventing initial bacterial adhesion and subsequent development of a bacterial biofilm in vitro.

Three cements Simplex unloaded, Simplex with erythromycin and Simplex with tobramycin were mixed in a conventional manner, ie vacuum hand mixing in sterile conditions and then injected into pre-moulded PTFE coated cylinder moulds yielding 8 cylinders in each group. The cement cylinders were then removed and exposed to a known pathogenic strain of staphylococcus aureus ATCC—29213-NCTC 12973 in solution 3x106 Colony forming units CFH/ml) for 15 minutes. The cylinders were then removed and cultured for 24 hours at 37°C in RPMI with Glutamine. Cylinders were then removed and subjected to rinsing in PBS to remove any non-adherent bacteria. Cylinders were then sonicated at 50 Hz in Ringer’s solution and adherent biofilms were serially log diluted and plated on Columbia blood agar. Colonies were counted manually. Control cylinders of unloaded cement showed 120,000 CFU/cm2 of adherent bacteria whereas loaded cement erythromycin and tobramycin showed 500 and 80 CFU/cm2 respectively (p< .0005 Student t-test).

This study shows that loaded cement does not prevent biofilm adhesion in its initial reversible stages whereas unloaded cement does not. This is important since most infected implants are infected at time of primary operation and cements anti-bacterial role beyond the first 48 hours remains questionable, when inflammatory encapsulation of the implant begins. We would therefore question the usage of unloaded cement in primary arthroplasty surgery.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_II | Pages 139 - 140
1 Feb 2003
Soffe K Sheehan E McKenna J McCormack D
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Introduction: While the incidence of infection associated with hip and knee prosthesis is low, with the increasing number of arthroplasties being carried out, the total number of such cases is increasing. Also increasing is the number of multi-resistant organisms. These factors have raised questions regarding the optimal antibiotic impregnated cement for use in both spacers and in cemented revisions.

While gentamycin, erythromycin, cefotaxime and vanomycin have a proven record as effective thermostatic antibiotics, newer antibiotics teicoplanin (although used in clinical practice) are as yet untested.

Aim: To investigate the effectiveness of teicoplanin impregnated cement against a Staph Aureus.

Method: A pure culture of Staphlococcus Aureus with known antibiotic sensitivities was obtained. Six batches of Palacos cement were mixed without under sterile conditions. One batch contained cement alone. The other 5 batches were mixed with one of gentamycin, vancomycin, erythromycin, cefotaxime and teicoplanin.

Group 1: A pure culture of over 60 colonies was grown on 5 Columbian blood agar plates. A 1cm spherical sample of each batch of the cement was placed on each plate at regular intervals and allowed to heat and harden.

Group 2: A further 1cm spherical ball of cement from each batch were placed on a further 5 blood agar plates which were then inoculated with the Staph Aureus and the cement was allowed to heat and harden.

Group 3: 24 hours later, the cement was placed on a further 5 blood agar plates which were then inoculated with the Staph Aureus.

Results: Group 1: None of the cement groups had any effect on the established colonies of Staph Aureus.

Groups 2 & 3: The cement without antibiotic had no effect on the growth of the antibiotic even when allowed to heat on the plate. All the other groups including the teicoplanin impregnated cement both initially and after 24 hours, caused a zone of inhibition, ie prevented bacterial growth.

Conclusion:

Heat alone did not affect the growth of the bacteria.

None of the antibiotic impregnated cement batches had any effect on an established growth of Staph Aureus indicating the effect of antibiotic impregnated cement may be bacteriostatic rather than bacteriocidal.

Teicoplanin is thermosable and is effective in the short term at least at halting the growth of Staph Aureus.

Addition of antibiotics to cement may change the biomechanical properties of the cement. It was noted that it took on average twice as long for the teicoplanin-impregnated cement to harden. Further investigations into this are ongoing.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_II | Pages 140 - 140
1 Feb 2003
Soffe K Sheehan E McKenna J McCormack D
Full Access

Aim: To investigate the effect of manipulation of the electrochemical environment around metallic implants on bacterial biofilm formation.

Background: The inability to prevent and treat prosthetic bacterial infection is a significant orthopaedic problem. Current antimicrobials are ineffective against bacterial biofilm communities. It is hypothesised that the alteration of the micro-environment could inhibit bacterial adhesion sufficiently to prevent biofilm formation allowing normal tissue integration to occur. Previous work by this group using zinc caused increased bacterial biofilm formation. Platinum being at the opposite end of the galvanic spectrum should cause the opposite effect.

Materials and Methods: Titanium 2mm Kirschner (K) wires (N=14) and Stainless Steel K wires (N=14) were cut into 50mm segments and sterilised. These were inoculated with either Staphylococcus Epidermitis (NC011047) or Staphylococcus Aureus (NC012973) suspensions. Superficial, non-adherent bacteria were removed by serial rinsing in phosphate buffered solution (PBS).

The K wires were added to either the culture media alone or the culture media containing platinum and incubated at 37 degrees for 24 hours. The wires were then removed from the media and rinsed in PBS. Samples were subjected to sonication, to fragment biofilms thereby releasing the bacteria, which were then quantified by serial log dilution technique and manual counting.

The presence of platinum reduced the adhesion of both Staph Aureus and Staph Epidermidis to stainless steel. This reduction was statistically significant using paired t-test (SPSS version 6.0). There was a significant reduction of adhesion with platinum in the Staph Aureus and titanium group while the reduction in the Staph Epidermidis and titanium group did not reach statistical significance.

Conclusion: The use of platinum to manipulate the microcurrent around metallic implants reduces bacterial biofilm formation in vitro. This has obvious clinical implications in prevention of implant infections.