Infection after knee arthroplasty is a devastating complication. Our aim is to present our outcomes of treating infected knee replacements at a tertiary referral centre.

We performed a consecutive, retrospective case series of all revision knee arthroplasty for infection between January 2006 and December 2008. Case notes were reviewed and data collated on the date and institution of primary arthroplasty, procedures undertaken at our institution, microbiology and bone loss post first stage, serological markers (C-reactive protein, ESR) prior to second stage and outcome.

During this three year period we performed 430 knee revision operations. 51 were in the presence of deep chronic infection. 90% were referred from other hospitals. Overall infection was successfully eradicated in 69%.

Nineteen patients underwent repeat two-stage and overall eleven (58%) patients had successful eradication of infection with multiple two-stages. Of these 47% had F3/T3, the highest grading of Anderson Orthopaedic Research Institute bone loss indicating no metaphyseal bone. A further 12% had bicondylar deficiency on the tibia and no femoral metaphyseal bone (F3/T2b).

Multidrug resistance present in 69% and 47% were infected with multiple organisms. All members of the unsuccessful outcome group had at least one multidrug resistant organism compared to 43% in the successful cohort (P=0.0002). Multiple organisms are associated with an unsuccessful outcome (P=0.056).

Serological markers were not significantly different between the successful and unsuccessful outcome groups.

Where the referring hospital had attempted revision and failed, the chance of eradicating infection dropped from 75% to 58% and the rate of above knee amputation was twelve times higher (3% vs. 36%).

Custom constrained, rotating hinge prostheses enable aggressive soft tissue debridement including ligaments. Successful two-stage requires a multidisciplinary approach including tissue viability nurses, microbiologists and plastic surgeons. Where units lack revision expertise this series suggests early referral increases the chance of limb salvage.

Plasma levels of cobalt and chromium ions and Metal Artefact Reduction Sequence (MARS)-MRI scans were performed on patients with 209 consecutive, unilateral, symptomatic metal-on-metal (MoM) hip arthroplasties. There was wide variation in plasma cobalt and chromium levels, and MARS-MRI scans were positive for adverse reaction to metal debris (ARMD) in 84 hips (40%). There was a significant difference in the median plasma cobalt and chromium levels between those with positive and negative MARS-MRI scans (p < 0.001). Compared with MARS-MRI as the potential reference standard for the diagnosis of ARMD, the sensitivity of metal ion analysis for cobalt or chromium with a cut-off of > 7 µg/l was 57%. The specificity was 65%, positive predictive value was 52% and the negative predictive value was 69% in symptomatic patients. A lowered threshold of > 3.5 µg/l for cobalt and chromium ion levels improved the sensitivity and negative predictive value to 86% and 74% but at the expense of specificity (27%) and positive predictive value (44%).

Metal ion analysis is not recommended as a sole indirect screening test in the surveillance of symptomatic patients with a MoM arthroplasty. The investigating clinicians should have a low threshold for obtaining cross-sectional imaging in these patients, even in the presence of low plasma metal ion levels.

Purpose

Late stage medial unicompartmental osteoarthritic disease of the knee can be treated by either Total Knee Replacement (TKR) or Unicompartmental Replacement (UKR). As a precursor to the TOPKAT study this work tested the postulate that individual surgeons show high variation in the choice of treatment for individual patients.

Background: The exact incidence of cancer (primary/metastatic) leading to pathological fracture in femoral neck is not clear. Bone specimen is often sent for histology in suspicious cases. This retrospective study was aimed to answer the above question and to review our hospital practice in managing these patients.

Materials & Methods: All patients with fracture neck of femur undergoing surgery and had bone specimen taken for histo-pathological examination between 01.01.2002 and 31.12.2003 were included. Case notes and histology reports were reviewed.

Results: Out of total 533 patients with femoral neck fracture, 32 (6%) patients had bone specimen taken for histology. 9 male & 23 female patients with mean age of 82 years. 58% had past history of cancer (commonest being breast) with/without suspicious lesion on x-rays where as the remaining had no history of cancer but suspicious lesion on x-rays. 4 (12.5%) had positive histology results. All four had metastatic disease (2 from breast, 1 from renal and 1from multiple myeloma). Only 19% had results documented in case notes but 81% had reports filed in notes. Appropriate referral was made to oncology team for three patients. The fourth patient with multiple myeloma died in hospital before the referral. Four of 28 (14%) patients with negative results died within 3 years following the surgery compared to only 1 (multiple myeloma) out of 4 patients with positive results.

Conclusion: The incidence of suspicious pathological femoral neck fracture was 6% but incidence of cancer was 0.7%. All positive cases were metastatic. Commonest primary was from breast – adenocarcinoma). Mortality in negative cases was 16% at average of 3 years compared to 25% in metastatic fracture patients.

Introduction: It was noted that INR levels transiently increased before dropping after stopping warfarin pre-operatively in warfarinised patients with femoral neck fractures. Surgery was more likely to be delayed in these patients. The aim of this retrospective study was to determine the trend of INR level after stopping warfarin and to determine the morbidity and mortality in these patients.

Material and Methods: All patients with femoral neck fracture who were on warfarin between 01.01.2002 and 31.12.2003 were included. Case notes and haematology reports were reviewed.

Results: 22 (4.2%) out of 533 patients with femoral neck fractures were found to be on warfarin on admission. 21 case notes were obtained. 7 male and 14 females with mean age of 81 years. In 11 (52%) cases, INR level increased before coming down after stopping warfarin. 60% of them had morphine as analgesic compared to 40% in the other group. Average rise in INR was 0.4. Average delay in surgery due to high INR was 3.5 (range 1–8) days. It took average of 4 days to achieve desirable INR after restarting warfarin. 6 (28%) needed blood transfusion. Nine (43%) patients developed complications including: intra-operative bleeding-1, postoperative DVT-1, fast AF-2, post-operative anaemia-1, other medical-3. One patient (5%) died from large CVA 12 days after surgery. No further mortality was found within 30 days of surgery.

Conclusion: Incidence of femoral neck fractures on warfarin was 4.2%. In over half of the cases, the INR level went up before going down after stopping warfarin. Morphine may be responsible for this trend. Delay in surgery does not seem to increase mortality or morbidity compared to published studies.

The correct positioning of implant components in total knee replacement (TKR) is important for a successful long-term outcome. In order to address the problems inherent with conventional alignment methods, several computer-assisted navigation systems (CAS) have been developed. Despite numerous reports of clinical outcomes and system reliability, there is a lack of studies independently evaluating the precision and accuracy of such systems. We report on the design and development of a method and device to evaluate the accuracy of such a computer-assisted navigation system in two situations; 1) Normal or near-normal lower limb mechanical axis, and 2)Simulated femoral and/or tibial extra-articular deformity in either varus/valgus (x), internal/external rotation (y) or flexion/extension (z) planes.

The system assessed was the Ci Knee-CAS navigation system (BrainLab/De Puy). This image-free system requires the registration of specific anatomical points to identify the mechanical axis of the lower limb and therefore provide information on resection level and alignment. In order to precisely measure and accurately reproduce these points we constructed a phantom device along anatomical guidelines, with lockable joints located at the mid-shaft of both femur and tibia. We then identified geometric CAS data; 1) Tibial resection height, and 2) Tibial resection plane, and using specially written software compared this against validated co-ordinate measurements independently obtained by a FaroArm co-ordinate measurement system (FARO Technologies, USA). This enabled data from the navigation system to be directly compared against highly accurate reference measurements.

Accuracy of the system was then assessed with both normal mechanical alignment of the lower limbs and simulated extra-articular deformity.

To determine the effect of experience of the operator and the effect of type of anaesthesia used on re-manipulation rates of fracture distal radius manipulated in A& E, a retrospective review of distal radius fractures manipulated in A& E between January 2000 and January 2001. Operators were divided into two categories: junior (SHO grade) and senior (higher grade) doctor.

54 patients with fracture distal radius had manipulation in A& E. 15 male and 39 female patients with mean age of 61 years (52 for males and 63 for females) were included.

42 (78%) fractures were manipulated under haematoma block (18 by junior, 23 by senior doctor) and 12 (22%) fractures were manipulated under Bier block (1 by junior, 11 by senior doctor). Operator’s grade was not clearly mentioned in one case. 13 out of 54 patients (24%) needed fracture re-manipulation under general anaesthesia. 12 out of 42 fractures manipulated under haematoma block (30%) needed re-manipulation compared to only one out of 12 fractures (8%) manipulated under Bier block (p=0.25). 9 out of 19 fractures manipulated by junior doctors needed re-manipulation compared to only 4 out of 34 fractures manipulated by senior doctors (p=0.007). Haematoma block was used for 18 out of 19 cases by junior doctors and for 23 out of 34 cases by senior doctors (p=0.038). Average number of fracture clinic follow-ups was 4 (range 2 to 8).

Junior doctors had significantly higher preference for haematoma block and significantly higher re-manipulation rate. Re-manipulation rates were higher with fractures manipulated under haematoma block compared to Bier block.

Adequate training and supervision should be provided for SHOs while performing such procedures in A& E. Use of Bier block as a regional anaesthesia for manipulation of distal radius fractures in A& E should be encouraged.

The Phantom based Computer assisted orthopaedic surgical system (CAOSS) has been developed collaboratively by the University of Hull and the Hull Royal Infirmary, to assist in operations like dynamic hip screw fixation. Here we present summary of our system.

CAOSS comprises a personal computer based computer system, a frame grabber with video feed from a C-arm image intensifier, an optical tracking system and a radiolucent registration phantom which consists of an H arrangement of 21 metal balls. The phantom is held in position by the optically tracked end-effector. Knowing the optical position of the phantom, a registration algorithm calculates the position of C-arm in coordinate space of the optical tracking system.

Computer based planning uses an anteroposterior (AP) and lateral image of the fracture. Marks are placed on the 2D projections of femoral shaft, neck and head on the computer screen, which are then used to create 3D surgical plan. The computer then plans a trajectory for the guide wire of DHS. The depth of the drill hole is also calculated. The trajectory is then shown on both AP and lateral images on the screen.

CAOSS meets all the requisite of electrical and electromagnetic radiation standards for medical equipment. There has been extensive validation using software simulation, performance evaluation of system components, extensive laboratory trials on plastic bones. The positional accuracy was shown to be within 0.7mm and angular accuracy to be within 0.2°. The system was also validated using Coordinate Measurement Machine.

Our system has the unique feature of the registration phantom which provides accurate registration of the fluoroscopic image.

Introduction and Aims Back pain patients usually demand more time in clinic. A significant proportion of this time is spent in performing clinical examination. It has been recognised that detailed history of symptoms is the backbone in reaching the diagnosis and deciding the management plan for patients with lower back pain and/or radiculopathy. The aim of the study was to look at 1) Contributions from History and Examination. 2) Does Clinical Examination add any further information not identified from history?

Method A prospective, blinded study was carried out to determine the usefulness of history and clinical examination, individually to reach the diagnosis and plan the management. 75 consecutive lower back pain and/or radiculopathy patients were included in the study. Two orthopaedic registrars saw all the patients. One took detailed history and the other registrar performed clinical examination. Both registrars based on their information arrived at a provisional diagnosis. A consultant also took history and examined these patients. MRI scan was done as per clinical indication.

Results The data was analysed using standard statistics software. In all patients history suggested the possible diagnosis. Clinical examination did not add any further information to alter the course of management, which was planned for the patient. Clinical examination did not show any further information that was not identified in the MRI scan.

Conclusion Clinical examination does not add to the body of information available from history. Clinical examination does not add any further information not available on the scan. Clinical examination should be performed for patients considered for surgery to document the findings; here both subjective and objective assessment should be performed. Examination is not a useful screening tool.

Introduction and Aims: Lower back and/or leg pain is a symptom of a number of pathological conditions involving lumbosacral nerve roots. Disc herniation is one of the most common causes of LBP (after mechanical back pain). There is controversy regarding the progression of disc degeneration and/or lower back pain to symptomatic disc prolapse over time.

Method: The aim of the study was to determine the natural progression of patients with lower back pain/disc degeneration established clinically and on MRI to symptomatic disc herniation over three to six years. Total of 970 patients who had an MRI scan between January 1998 and September 2000 were included in the study. Information about disc pathology, level and number of discs involved were recorded from MRI scan reports. A short questionnaire was sent to all patients. It contained 10 questions regarding current status of pain and neurology, any treatment in form of back injection and operation, current occupation and smoking status.

Results: The collected data was analysed using standard statistics software (SPSS). The results will be discussed.

Conclusion: The information provided by this study will be useful in judging the natural progression of lower back pain and/or disc degeneration to a symptomatic prolapse intervertebral disc. It will also be useful in medico-legal cases where patients had pre-existing disc degeneration and subsequently developed disc herniation over time.

Introduction and Aims: Back pain patients usually demand more time in clinic. A significant proportion of this time is spent in performing clinical examination. It has been recognised that a detailed history of symptoms is the backbone in reaching the diagnosis and deciding the management plan for patients with lower back pain and/or radiculopathy.

Method: A prospective, blinded study was carried out to determine the usefulness of history and clinical examination, individually, to reach the diagnosis and plan the management. Sixty consecutive lower back pain and/or radiculopathy patients were included in the study. All the patients were seen by two orthopaedic registrars. Detailed history was taken by one and clinical examination was performed by the other registrar. A provisional diagnosis was made by both registrars based on their information. A consultant also took history and examined these patients. MRI scan was done as per clinical indication.

Results: The gathered information was analysed using standard statistics software. The data indicates that clinical examination on its own was non-contributory in reaching diagnosis and plan the management. All information obtained by history alone correlated well with MRI results. The full results and cost implications will be discussed.

Conclusion: Routine clinical examination of spine can be omitted without compromising the patient care, where clear history is available to reach diagnosis and plan the management. Clinical examination should be performed on those patients who need surgery to document the pre-operative neurology.

Introduction and Aims: Achieving bloodless surgical field is vital for any arthroscopy surgery. Olszewski et al showed that dilute adrenaline saline irrigation (1mg/l) improves the clarity of operative field by reducing the bleeding. Jensen et al also showed that dilute adrenaline saline irrigation (0.33mg/l) is beneficial in achieving bloodless field in shoulder arthroscopy.

Method: A prospective, randomised, double blind, control trial was carried out to determine the effect of adrenaline (epinephrine) in knee arthroscopy without tourniquet. Ethics Committee approval was obtained for this study. A Doctors/Dentists Exemption Certificate (DDX) was obtained from Medicines Control Agency (UK govt) for use of adrenaline (epinephrine) in this trial. All patients undergoing knee arthroscopy were randomised into two groups: 1) to have dilute adrenaline (1 mg of adrenaline into three-litre bags of normal saline (0.33mg/l) for irrigation); and 2) not to have dilute adrenaline in normal saline irrigation.

Results: A total of 40 patients (24 male and 16 female) were included in the trial. All operations were performed using pressure-controlled pump system (75 mm Hg). No tourniquets were used. A visual analogue score (VAS) of zero to 10 (worst to best) was used by the surgeon to determine the clarity of surgical field at the end of operation. Mean age was 46.5 years (IQR 27–63 years). Twenty patients had dilute adrenaline saline irrigation and 20 had normal saline irrigation. Mean VAS was 8.5 (IQR 6 – 10). Mean VAS for group 1 was 8.4 and for group 2 was 8.7 (p= 0.59). There were no intra-operative or immediate post-operative complications noted in either group.

Conclusion: The study failed to identify any benefit of using adrenaline (epinephrine) in normal saline irrigation fluid in terms of achieving bloodless surgical field in knee arthroscopy. The study also conclude that pressure controlled pump system provides excellent bloodless surgical field in knee arthroscopy without tourniquet.