Preventing infections in joint replacements is a major ongoing challenge, with limited effective clinical technologies currently available for uncemented knee and hip prostheses. This research aims to develop a coating for titanium implants, consisting of a supported lipid bilayer (SLB) encapsulating an antimicrobial agent. The SLB will be robustly tethered to the titanium using self-assembled monolayers (SAMs) of octadecylphosphonic acid (ODPA). The chosen antimicrobial is Novobiocin, a coumarin-derived antibiotic known to be effective against resistant strains of Staphylococcus aureus.

ODPA SAMs were deposited on TiO₂-coated quartz crystal microbalance (QCM) sensors using two environmentally friendly non-polar solvents (anisole and cyclopentyl methyl ether, CPME), two concentrations of ODPA (0.5mM and 1mM) and two processing temperatures (21°C and 60°C). QCM, water contact angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and temperature-programmed desorption mass spectrometry (TPD-MS) were used to characterise the ODPA SAM. A SLB with encapsulated Novobiocin was subsequently developed on the surface of the ODPA SAM using fluorescent lipids and a solvent assisted method. The prototype implant surface was tested for antimicrobial activity against S. aureus.

A well-ordered, uniform ODPA SAM was rapidly formed using 0.5 mM ODPA in CPME at 21°C during 10 min, as confirmed by high Sauerbrey mass (≍285-290 ng/cm²), high atomic percentage phosphorus (detected using XPS) and high water contact angles (117.6±2.5°). QCM measurements combined with fluorescence microscopy provided evidence of complete planar lipid bilayer formation on the titanium surface using a solvent assisted method. Incorporation of Novobiocin into the SLB resulted in reduced attachment and viability of S. aureus.

Key parameters were established for the rapid, robust and uniform formation of an ODPA SAM on titanium (solvent, temperature and concentration). This allowed the successful formation of an antimicrobial SLB, which demonstrated potential for reducing attachment and viability of pathogens associated with joint replacement infections.

MHRA guidance for patients with metal on metal hip replacements (MOM) was provided in 2012 and updated in 2017 to assist in the early detection of soft tissue reactions due to metal wear debris. A large number of metal on metal hip replacements were undertaken at our trust. A program of recall for all patients with metal on metal hip replacements was undertaken and MHRA guidelines implemented.

Identification and recall of all patients from 2001 with MOM hip replacements using theatre logs, patient records and consultant log books. Two consultant review of X-rays and patient records. Postal questionnaires and GP requests for cobalt & chromium blood tests. Two consultant led MOM review clinics undertaken with metal artefact reduction scans (MARS) performed following consultation in 2017.

674 patients, 297 available for review. 59 refused follow up. 87 moved out of area, 36 untraceable, 26 not MOM, 147 RIP, 22 already revised. From 297 patients 126 female, 171 male, age range 39 – 95 yrs. 126 resurfacing, 171 MOM THR. 26 patients with elevated metal ions, MARS performed of which 17 positive, 9 negative. Of 17 positive scans 10 patients asymptomatic, 7 waiting revision.

A time consuming effort and additional resource was needed and supported by the trust. From 297 hips 17 positive MARs were identified (5.7%). A new database registry has been developed to track MOM patients, clinics set up for ongoing follow up with radiological protocols for imaging. An arthroplasty advanced nurse practitioner (ANP) is now trained reviewing patients independently.

Background

Post-operative pain following forefoot surgery can be difficult to control with oral analgesia so regional analgesic methods have become more prominent in foot and ankle surgery. It was the aim of this study to evaluate the efficacy of a combination of popliteal and ankle blocks and decide if they provide significantly better post-operative analgesia than ankle block alone in forefoot surgery.

Introduction: Ankle sprain is one of the common presentations in Accident and Emergency. Accurate diagnosis is critical and sometime difficult without special investigation such as Magnetic Resonance Imaging (MRI) or arthroscopy.

Aim: The purpose of this project was to evaluate magnetic resonance imaging (MRI) accuracy for diagnosing and defining ankle pathology.

Method: Retrospective review of 36 patients who underwent both MRI and Arthroscopy. All cases were seen by single orthopaedic surgeon with special interest in foot and ankle surgery. MRI scan were reviewed by consultant radiologist at our institute. Arthroscopy was used as a standard for comparing MRI results. Sensitivity and Specificity was calculated by qualified statistician.

Results: For osteochondral lesion the Sensitivity of 85.7 %, Specificity of 93.3% and Accuracy of 89.7% was noticed. Anterior and posterior tibiofibular ligament (ATFL and PTFL) pathology had a Sensitivity of 100 %, Specificity of 100% and Accuracy of 100%, while anterior inferior tibiofibular ligament pathology had a Sensitivity of 66.6 %, Specificity of 95% and Accuracy of 86.6%.

Conclusion: Although MRI is a useful tool in exclusion of pathological condition its sensitivity and accuracy in diagnosing ligament injury is not encouraging.

Background: Postoperative pain following forefoot surgery can be difficult to control with oral analgesia so regional analgesic methods have become more prominent.

Aim: It is the aim of this study to evaluate the efficacy of a combination of popliteal and ankle blocks and decide if they give significantly better postoperative analgesia than ankle block alone in forefoot surgery.

Methods: This is a prospective, randomised, controlled and single blind study. The total number of patients is 80 with 40 patients in the ankle block only group (control) and 40 patients in the ankle and popliteal block group. All patients underwent forefoot surgery. Postoperative pain was evaluated in the form of a visual analogue scale and verbal response form. Evaluations took place four times for each patient: in the recovery room, 6 hours postoperatively, 24 hours postoperatively and on discharge. The pain assessor, who helped the patient complete the pain evaluation forms, was blinded to the number of blocks used. The amount of opiate analgesia required whilst an inpatient was also recorded. On discharge the patient was asked to rate their satisfaction with the pain experienced during their hospital stay. Results were analysed using Mann-Whitney tests.

Results: Results show that pain is significantly less in recovery (p=0.044) and after 24 hours (p=0.0012) for those patients with combined blocks. Satisfaction with pain relief is also higher for these patients. No complications were found as a consequence of having two peripheral nerve blocks.

Conclusions: A popliteal block in conjunction with an ankle block does reduce postoperative pain significantly more than ankle block alone after forefoot surgery.