Osteonecrosis is a potentially devastating condition with poorly defined pathogenesis that can affect several anatomical areas with or without a previous traumatic insult. Post traumatic osteonecrosis (PON) in the foot and ankle has been commonly described in the talus and navicular but rarely in the distal tibia. PON of the distal tibia is a rarely reported and infrequent complication of fracture dislocations of the ankle. Its scarcity can lead to misdiagnosis and inappropriate management due to a lack of clinical knowledge or suspicion with resultant severe functional compromise. We aim to highlight the clinical and radiological features of PON of the distal tibia and report the findings in a series of four patients following a fracture dislocation of the ankle. Three patients sustained a SER4 fracture dislocation and one patient sustained a PER4 fracture dislocation in keeping with standard patterns of injury seen in most trauma units. In each case, PON of the distal tibia presented with progressive anterolateral tibial plafond collapse and valgus deformity of the ankle. The radiological features previously reported in the literature are based on plain film x-ray, CT and MRI but no description of SPECT-CT findings. One of the patients in the series underwent SPECT-CT following clinical suspicion of PON and thus we describe the findings not previously reported. Our objective is to highlight this rare condition as a potential cause for ongoing pain following fracture dislocation of the ankle as well as advocating the use of SPECT/CT as a useful imaging modality to aid in the diagnosis.

The conservative management if isolated humeral shaft fractures is a long, drawn out, painful process for the patient. For the clinician, it involves multiple clinic attendances and repeated radiographic assessment and brace alteration.

The primary reason for conservative management is the excellent results, but a very definite secondary consideration is the high incidence of shoulder pathology after I.M. nailing. This is thought to be due to rotator cuff pathology at the time of surgery. We question the validity of this second argument.

Ten consecutive humeral shaft fractures attending our unit had an MRI of both shoulders carried out during the initial stages of their injury. Two of the ten had retrograde nailing and the remainder was managed conservatively. While there was no patient with an occult coracoid fracture in association with the shaft fracture. We found eight out of ten to have significant signal changes in the subacromial space on the side of the fracture only.

We conclude that there is a significant occult injury to the shoulder at the time of humeral shaft fracture and this may in fact represent a cause for the high incidence of shoulder pain post fracture.

There are numerous ankle and hindfoot scores in existence, which have been devised and used to assess surgical interventions. All have in common that there has been little or no work done to demonstrate their validity, reliability or sensitivity to change. Which score one chooses to use for the assessment of outcome will at present depend largely on personal preference.

We have undertaken a study to assess four of the most commonly used scores, those of Mazur (1978), Takakura (1990), AOFAS (1994) and Kofoed (1995) as well as a little used but well designed score, The Foot Function Index (1991).

A cohort of twenty patients who had undergone a unilateral total ankle replacement (STAR) for rheumatoid or osteoarthritis were assessed by a single observer. The time following operation ranged from six to 48 months. All completed the above scores as well as a SF36 questionnaire. Using the SF36 as a “Gold standard” the scores were compared, both in terms of their overall results and also more specifically in terms of subsections such as pain and function.

Our results, though not to be interpreted as validation, do give some rational basis for the choice of score to use in assessing total ankle replacements.

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.

Metallic implants are used frequently in the operative repair of joints and fractures in orthopaedic surgery. Orthopaedic implant infection is chronic and biofilm based. Present treatment focuses on removing the infective substratum and implant surgically as well as prolonged anti-microbial therapy. Biofilms are up to 500 times more resistant than planktonic strains of bacterial flora to antibiotics. Silver coatings on polymers and nylon (catheters, heart valve cuffs, burn dressings) have shown inhibition of this biofilm formation in its adhesion stage. Our aim was to deposit effective, minute, antibacterial layers of silver on orthopaedic stainless steel and titanium K-wires and to investigate the effect of these coatings when exposed to Staphylococcus Aureus biofilms in an in vitro and in vivo environment.

Combining magnetron sputtering with a neutral atom beam (Saddle Field) plasma source at 10⁻⁴ mbar in argon gas at temperatures of 60°C, a silver coating of 99.9% purity was deposited onto stainless steel and titanium orthopaedic K-wires. Coating thickness measurements were obtained using glancing angle x-ray diffraction of glass slides coated adjacent to wires. Magnetron parameters were modified to produce varying thickness of silver. Adhesiveness was examined using Rockwell punch tests. Silver leaching experiments were carried out in phosphate buffered saline at 37°C for 48 hours and using inductive coupled plasma spectrometry to assess leached silver ions. Surface microscopy visualised physical changes in the coatings.

Biofilm adhesion was determined by exposing wires to Staphylococcus Aureus ATCC 29213 – NCTC 12973 for 15 minutes to allow biofilm initiation and adhesion. Wires were then culturing for 24 hours at 37°C in RPMI. Subsequently, wires were sonicated at 50Hz in ringer’s solution and gently vortexed to dislodge biofilm. Sonicate was plated out by log dilution method on Columbia blood agar plates. Bacterial colonies were then counted and changes expressed in log factors.

K-wires were coated with 1 to 50 nm of silver by running the magnetron sputtering at low currents. These coatings showed excellent adhesive properties within the 48 hours exposed with only 3.7% of silver leaching in buffered saline. The silver coated stainless steel wires showed a log 2.31 fold reduction in biofilm formation as compared to control wires (p< .001), Student t-test), the silver coated titanium wires showed a log reduction of 2.06, (p< .001, Student t-test). Animal studies demonstrated enormous difficulty in reproducing biofilm formation and showed a 0.49 log fold reduction in the titanium group when exposed to Staph Aureus (p< .01, Student t-test), the other groups showed no statistically significant reduction.

We have perfected a method of depositing tiny layers of anti-bacterial silver onto stainless steel and titanium, which is anti-infective in vitro but not in vivo. Further studies involving other metal coatings such as platinum and copper are warranted.

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.

Abstract: The early stages of ankle arthroplasty were complicated by unsatisfactory surgical results and poor patient satisfaction. This paper reveals far greater patient satisfaction and excellent surgical results achieved from the STAR uncemented ankle replacement.

Materials and Methods: We reviewed the first 29 STAR ankle replacements carried out by the senior author. Patients were reviewed clinically and radiographically according to the AAOS hind-foot score. Failure was deemed to be revision of the implant. Reason for surgery was rheumatoid arthritis in twelve patients and primary or secondary osteoarthritis in seventeen patients.

Results: One patient required revision surgery. This was an osteopoenic rheumatoid patient and the revision was for component subsidence. Three patients from the initial stages required minor soft tissue and bony resection at a second procedure with retention of the prosthesis. Patient satisfaction was high. Clinically, the average ROM was 5deg dorsiflexion and 12 deg plantarflexion. Patient satisfaction was extremely high. While the AAOS score does not give a grading, we also applied the Kofoed scale and 28 of our patients achieved a good or excellent result.

Conclusion: We conclude that the STAR uncemented ankle replacement achieves very good clinical results and excellent patient satisfaction.

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.

Metallic implants are used frequently in the operative repair of joints and fractures in orthopaedic surgery. Metal infection is a catastrophic complication of the surgery with patients loosing their newfound mobility and independence, associated morbidity and mortality is high. Orthopaedic implant infection is chronic and biofilm based. Present treatment focuses on removing the infective substratum and implant surgically as well as prolonged anti-microbial therapy. Biofilms are 500 times more resistant than planktonic strains of bacterial flora to antibiotics, and with evolving resistant strains this form of therapy is loosing ground. Silver coatings on polymers and nylon (catheters, heart valve cuffs, burn dressings) have shown inhibition of this biofilm formation in its adhesion stage. Our aim was to deposit effective, minute, biocompatible, anti-bacterial layers of silver on orthopaedic stainless steel K-wires.

Combining magnetron sputtering with a neutral atom beam (Saddle Field) plasma source at 10⁻⁴ mbar in argon gas at temperatures of 60°C, a silver coating of 99.9% purity was deposited onto stainless steel orthopaedic K-wires. Coating thickness measurements were obtained using glancing angle x-ray diffraction of glass slides coated adjacent to wires. Magnetron parameters were modified to produce varying thickness of silver. Adhesiveness was examined using Rockwell punch tests and tape tests. Silver leaching experiments were carried out in phosphate buffered saline at 37°C for 48hrs and using inductive coupled plasma spectrometry to assess leached silver ions. Surface microscopy visualised physical changes in the coatings. Biofilm adhesion was determined by exposing wires to Staphylococcus aureus ATCC 29213 -NCTC 12973 for 15 min to allow biofilm adhesion and initiation. Wires were then cultured for 24h at 37°C in RPMI. Subsequently wires were sonicated at 50Hz in ringer’s solution and gently vortexed to dislodge biofilm. Sonicate was plated by the log dilution method on blood agar plates. Bacterial colonies were then counted and changes expressed in log factors. Surface biofilms were visualised using scanning electron microscopy. Cytotoxicity was assessed using fibroblast cell cultures lines.

K-wires were coated with 5 to 50 nm of silver by running the magnetron sputtering at low currents. These coatings showed excellent adhesive properties within the 48hr exposed with only 5% of silver leaching in buffered saline. The silver coated wires showed a log 3–4 fold reduction in biofilm formation as compared to control wires. The coatings showed no cytotoxic effects.

Silver coating of medical implants has been shown in urological catheters to reduce biofilm infection. We have perfected a method of depositing thin layers of anti-bacterial silver onto stainless steel, which is both anti-infective and biocompatible. This coating could potentially add to the armourary of anti-infective agents in the elimination of infection related orthopaedic implant failure.

Infection around implanted biomaterials in humans is a major healthcare issue and current ability to effectively prevent and treat such infections using antibiotics is limited. The hypothesis of the study was that surface charge could be manipulated to a positive state and thus moderate bacterial adhesion to the implant. The surface charge was manipulated by creating a galvanic cell using a zinc strip in a standard suction drain.

Adhesion of Staph. aureus and Staph. Epidermidis to stainless steel and titanium implants in vitro and in vivo was quantified by sonication and log dilution technique. The response to this surface manipulation of charge varied for both the bacterial species and the type of metallic implant. In vitro studies produced an 88% reduction in Staph. aureus adhesion to stainless steel and a 36% reduction in adhesion to titanium. However Staph. epidermidis showed an increased adhesion to stainless steel (Log 1.81 ± 1.12 in vitro) and to titanium (log 1.80 ± 0.12). Staph aureus demonstrated a log increase of 1.56± 0.09 in adhesion to titanium in vivo while Staph. epidermidis generated a log increase of 3.97± 0.10 in adherent bacteria.

In this experiment we have shown that alteration of the electrochemical environment around an implant influences bacterial adhesion. While our technique is not therapeutically viable, further manipulation of surface charge of an implant is possible using other electroactive materials. This may be explored in the prophylactic treatment of implant infection

Patients with hemiplegic cerebral palsy walk with a well recognised characteristic gait pattern. They also commonly have a significant leg length discrepancy which is less well appreciated. The typical equinus gait in these patients is assumed to be an integral part of the disease process of spasticity and a tendency to develop joint contractures. However an alternative explanation for the presence of an equinus deformity may be that it is a response to the development of a significant leg length discrepancy in these patients. The development of such an equinus deformity would have the effect of functionally lengthening the short hemiplegic leg. We set up a study to examine the correlation between leg length discrepancy and equinus deformity. We reviewed the gait analyses and clinical examinations of 183 patients with hemiplegic cerebral palsy. While 22% had no significant leg length discrepancy, 65% had a measured discrepancy of greater than 1cm. There was a linear correlation between age and limb length discrepancy. We also found that there was a linear relationship between leg length discrepancy and ankle equinus at the point of ground contact. We propose that the equinus deformity seen in the hemiplegic cerebral palsy patient is multifactorial and is related not only to the disease state but also to the presence of leg length discrepancy. The equinus deformity functionally lengthens the short hemiplegic leg. Indeed it may represent an attempt by these patients to functionally equalise their leg lengths. This factor must be taken into account when considering correction of an equinus deformity in patients with hemiplegic cerebral palsy in order to avoid either recurrence of the deformity or the production of functionally unequal leg lengths. We have also highlighted the presence of significant shortening of the hemiplegic leg in these patients.