The documentation of deep infection rates in joint replacement is fraught with multiple difficulties. Deep infections acquired in theatre may present late, but some later presenting deep infections are clearly haematogenous, and not related to surgical management. The effect of Ultra Clean Air on infection rates was published by Charnley in 1972 (CORR,87:167–187). The data is valuable because large numbers of THRs were performed in standard and Ultra Clean theatres, and detailed microbiology of the air was also recorded. No IV antibiotics were used, so only the effect of air quality was studied.

We extracted the data on theatre type and numbers from Table 3, and numbers and intervals from surgery of deep infections from Table 7. Theatre types with 300 air changes per hour and 3.5 CFU/M³ were classified as Ultra Clean. A logistic regression model was used to examine the effect of theatre type and time elapsed after procedure on the probability of becoming infected.

The model suggests that, controlling for time period, Ultra Clean Air is associated with a significantly lower probability of infection, with an OR of 0.30, p = 2.74 × 10⁻⁶. The effect is larger earlier post-surgery, but it does persist. The results are best reviewed as a graphic, which shows that Ultra Clean Air clearly affects the deep infection rate for up to four years post-surgery.

Ultra Clean Air reduces infection rates for up to four years post-surgery, so it is safe to assume that infections presenting after this are haematogenous. Ultra Clean Air does not eliminate early deep infection, so some early infections are not related to air quality. It is not practical to undertake widespread detailed retrospective analyses of cases. When monitoring infection rates there needs to be a balance between failing to record infections related to surgical technique and waiting many years to record low numbers of very late presenting problems. We suggest that registries should regard infections documented within three years of surgery as treatment complications.

For any figures or tables, please contact the authors directly.

Objectives

The osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) balance is of the utmost importance in fracture healing. The aim of this study was therefore to investigate the impact of nonosteogenic factors on OPG and RANKL levels.

Introduction

Operating theatre airflow can be measured using pulsed lasers (particle image velocimetry) but the process is difficult to do in 3D. Cup, vane or hot wire anemometers provide only 2D information. 3D measurements enable better understanding of airflow.

Aim

Prosthetic joint infection (PJI) is a major complication in THA. Nasal carriage with S. Aureus is a well-defined risk factor for infection in hospitalized patients. Risk for infection is reduced up to 50% by eradication therapy. Since PJI rates are very low and only 25% of the population are carriers, significant differences are hard to show and reports on PJI have been inconclusive. We analysed the effect of S. Aureus eradication therapy in THA.

As a result of laser imaging studies in an ultraclean theatre we concluded that obstructions to horizontal airflow at the periphery might produce areas of high particulate residence times. High residence times may allow a higher proportion of infected particles to land. We decided to investigate this effect by placing settle plates in defined positions on instrument trays during surgery.

In an initial study contamination was 0.25 colonies/plate/hour. When the surgeon, assistant and scrub person all used a body exhaust system the contamination rate was 0.04 colonies/plate/hour. We then organised the instrument tables with two large tables orientated so that the scrub person did not have to stand between the airflow and the table. We placed plates on both trays with the locations recorded.

With the instrument trolleys in optimised positions the contamination rate remained consistently at 0.04 colonies/plate/hour. An animation was produced showing how the bacterial colonies appeared over 18 hours of surgery. The majority of the contamination occurred on the surgeons’ side trolley at the opposite end of the trolley to the surgeon.

Ultraclean enclosures in the UK are specified by HTM03-01, which sets a standard of <10 cfu/cubic meter measured by active air sampling. The measurement does not however take place during surgery, as it is very difficult to perform air sampling during surgery. There is a reasonable correlation between air contamination and settle plates so they are a viable method for during surgery monitoring.

In a modern operating enclosure, using body exhausts, our contamination rate compares favourably to the fourth phase of Charnley's classic study in which he used 300 air changes/hour in the prototype closure. The rate compares favourably to the multi-centre Italian GISIO-ISChIA study. The contamination rate achieved could form a basis for comparative audits based on realistic during surgery monitoring.

Introduction

Studies show that cup malpositioning using conventional techniques occurs in 50 to 74% of cases defined. Assessment of the utility of improved methods of placing acetabular components depends upon the accuracy of the method of measuring component positioning postoperatively. The current study reports on our preliminary experience assessing the accuracy of EOS images and application specific software to assess cup orientation as compared to CT.

Introduction

Deep prosthetic joint infection is a major cause of morbidity. Previous work has shown that infected skin scales shed by members of staff in the operating theatre are the key source of infection. Much attention has been given to the design of ultra clean operating theatres but remarkably little attention has been given to factors controlling skin scale shedding.

The aim of this study was to develop a novel method of direct visualisation and quantification of skin scales and to assess the effect of a simple skin care regimen on skin scales.

The resection of distal femur and proximal tibia during TKR is 90° to mechanical axis but in a normal knee, the joint line is 3°varus. We measured various angles on long-leg alignment radiographs. The mean age was 58.7 years. The mean HKA axis was 4.3°± 0.5°, mPTA was 3.8°±0.5°, mLDFA was 3.6±0.5° and aLDFA was 8.6°±0.5°. The mean HKA & MPTA were approximately 4°varus, mLDFA 4° valgus & aLDFA 8°valgus. The alignment of the knee to its mechanical axis during TKR is therefore not anatomic. This raises a question whether the knee should be aligned to its kinematic axis instead of mechanical axis.

Computer-assisted navigation during total knee replacement has been advocated to improve component alignment and hence reduce failure rates and improve quality of life. The technique involves the placement of trackers via pins placed in both the femur and tibia throughout the surgery. It has been proposed that complication rates are higher in knee arthroplasty when computer navigation is used, compared to when it is not, due to increased risks from the pin tracker sites. Potential risks from pin sites include infection, fractures of the tibia or femur and pin site pain. In this study we present the post-operative complication rates related to pin tracker sites of computer navigated knee arthroplasty from a single surgeon at one centre.

A database was compiled including all patients undergoing knee arthroplasty with computer navigation between January 2009 and December 2013 performed by a single surgeon at one centre. A retrospective study was undertaken having identified a total of 321 patients (642 pin sites) with 287 having undergone total knee replacement, 29 Uni-condylar knee replacement and five having undergone patellofemoral knee replacement. There 131 males and 190 females with a mean age of 69.4 [range 48–89]. There were no exclusions. The patient's notes were reviewed for any complications that occurred as a result of pin sites including infection, pin site pain and fracture.

Only one patient (0.03%) was identified with a superficial pin site infection that was successfully managed with oral antibiotics only. There were no fractures or other complications identified in any of the other patients.

In this series, the complication rates resulting from pin tracker sites was very low suggesting computer navigation does not increase the risks of knee arthroplasty. There were no cases of femoral or tibial fractures in this series, as have previously been reported. It is therefore likely that the technique of pin site placement is important in limiting the risk of complications. In this series a standard technique was used in all cases. Stab incisions are always used rather than a percutaneous technique and the wounds closed with clips and protected with dressings at the end of the surgery. Uni-cortical drilling is sufficient to provide stability of the trackers intra-operatively and minimises the risk of thermal necrosis therefore bi-cortical placement is avoided. Self-drilling pins are used on power and inserted perpendicular to the bone on high torque and low speed. The tourniquet is not inflated until after the pins have been inserted. It is thought that using this technique offers a safe method of pin tracker placement ensuring low complication rates.

Chondral damage within the knee commonly occurs during sport following direct trauma or following degeneration through overuse. Radio frequency energy chondroplasty (RFC) can be used as an alternative to mechanical chondroplasty in the arthroscopic treatment of chondral lesions. Current literature supports the theoretical advantage of RFC and purports to in vitro improvements in cartilage structure and function following RFC. We conducted a retrospective study of patients undergoing RFC for isolated chondral lesions in the knee and assessed the short term clinical benefits.

Retrospective analysis was completed of operative notes and arthroscopic images of all patients who underwent arthroscopic chondroplasty at the royal Devon and Exeter Hospital between January 2009 and June 2012. Inclusion criteria included 1 to 2 defined chondral lesions, less than 2cm2, of Outerbridge grade II-IV, treated via arthroscopic RFC. Exclusion criteria included diffuse articular cartilage damage, additional pathologies affecting the knee or subsequent further injuries or invasive procedures to the knee. Data was collected via a subjective and objective questionnaire assessing patient outcome.

35 patients met the inclusion criteria, 32 were successfully followed up. Male: female ratio was 16:16, with a mean age of 39.5 (range 19–60).

84% (n=27) of patients experienced a significant reduction in pain (mean reduction of 51%, p < 0.001) lasting until the time of study (median of 21 months, range 9 to 31 months). There was no correlation between change in symptoms and site and grade of chondral lesion. Pre-operative instability symptoms did not significantly improve following RFC. Satisfaction with treatment was in direct correlation with pain relief achieved.

Our study appears to support current literature by suggesting short term improvements to pain following the use of RFC on chondral lesions. Greater population size and longer follow-up are required to provide more significant conclusions.

Introduction

The goal of revision total hip arthroplasty (THA) for acetabular defects is to achieve the best stability and fixation with available host bone. Tritanium is a highly porous metal construct with a titanium matrix coating. We are reporting our experience of utilizing this material in patients with major acetabular defects.

Oxford hip and knee scores are being used by many heath care commissioners to determine whether individual patients are eligible for joint replacement surgery. Oxford scores were not designed for use in deciding whether patients are suitable for surgery and they are not validated as a triage tool. The aim of this study was to assess what effect these predetermined threshold Oxford Scores would have on a contemporary patient cohort.

An analysis was undertaken of 4254 pre-operative Oxford scores in patients who had already undergone either hip resurfacing, a total hip, total knee or unicompartmental knee replacement surgery at our institution between 2008 and 2011. We assessed how these scores would affect the decision making pathway determining which patients would be eligible for joint replacement surgery. We also evaluated the effects this would have on patients undergoing surgery in terms of gender, sex, age and type of arthroplasty.

22.4% hip resurfacings, 10.0% of total hip replacements, 7.5% total knee replacements and 11.0% unicompartmental knee replacements would have been declined on the Oxford Scores system. The selection criteria as set by the health care commissioners was found to be ageist as there was a bias against older patients obtaining surgery. There was a bias against different forms of arthroplasty, particularly those patients suitable for resurfacing or unicompartmental knee replacement. It was also sexist as it selectively excluded male patients from surgery.

Rather than using pre-operative Oxford scores to discern which patients are eligible for surgery, evaluation of patient factors which are reported to adversely affect the outcome of hip and knee replacement surgery, may offer a better solution to improving quality of care. Oxford scores are undertaken to benchmark a providers performance and not to decide on an individual's suitability for surgery.

Introduction

Direct lateral approaches to the hip require detachment and repair of the anterior part of the gluteus medius and minimus tendon attachments. Limping may occur postoperatively due to nerve injury or failure of muscle re-attachment. The aim of this study was to assess the integrity of abductor muscle repairs using a braided wire suture marker.

Osteotomy through the bare area of olecranon minimises the damage to articular cartilage in the trans-olecranon approach to the distal humerus. In this study we have identified a reliable and easily reproducible anatomical land mark to make sure that the osteotomy passes through the bare area.

Two methods were used to determine the line for the osteotomy, in the first a line from the lateral epicondyle perpendicular to the olecranon and in the second an intra-articular marker was used to determine the osteotomy. In 5 cadavers the osteotomy with lateral epicondylar line as a marker went 2 mm proximal to the bare area. Of the 5 cadavers dissected with a marker passed to the angle of olecranon the osteotomy went through the bare area of olecranon in three specimens and just proximal in the other two.

In conclusion a cheveron osteotomy with the base of the chevron on the lateral epicondylar line will be the ideal site to make sure that the osteotomy passes through the bare area of the olecranon.

Fractures of the shaft of the humerus are often treated conservatively in a hanging cast or a humeral brace. The conservative management of this fracture is often prolonged and quite uncomfortable for the patient. Some of the patients will need an operative fixation after a trial of conservative management.

We retrospectively looked at 72 consecutive patients with fractures of the shaft of the humerus that presented in our institution over a period of two years. The fracture pattern, treatment modality time to union and the number that needed operative fixation following a trial of conservative treatment was analysed. Of the 72 patients 4 were lost to follow-up. 45 patients had a 1.2.B or 1.2.C type of fracture and 23 had a 1.2.A type of fracture. 29 (41%) were successfully treated conservatively, 11 (16%) patients were operated as the primary procedure and 15 (22%) patients were operated due to delayed or non union. 13 (19%) patients were operated within 4 weeks of the fracture as their alignment was not acceptable on their weekly follow-up.

The average time to union in the patients treated conservatively was 22 weeks, while that of the patients treated primarily by open reduction and plating was 14 weeks (p-value<0.05). Patients who needed operation after initial conservative management required prolonged period of rehabilitation and union time was 32.2 weeks. At the time of fracture union 72% of the patients who had been treated conservatively had joint stiffness requiring physiotherapy, while only 18% of those who had an open reduction and internal fixation had stiffness and required physiotherapy. (p-value < 0.05).

In conclusion careful consideration should be given before it is decided to treat this fracture conservatively especially in the case of 1.2.A fracture pattern.

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.

Aim: To determine the clinical improvement and the radiological time to fusion as well as correction of the lordosis angle in patients undergoing anterior cervical interbody fusion with the use of a silicate substituted calcium phosphate ceramic (Si-CaP) (Actifuse™ Synthetic Bone Graft, ApaTech, Ltd., Elstree, UK) as the bone graft substitute in the cage.

Design: We conducted a prospective clinical and radiological study to evaluate the use of Si-CaP as bone graft substitute in anterior cervical fusion for degenerative cervical spondylosis.

Materials and methods: Thirty patients were selected prospectively by preoperative and postoperative clinical and radiological assessments. All patients were operated on by a single surgeon (D.A.J.). Neck disability index and visual analogue score were used for the clinical assessment. Radiological assessment included improvement in the lordosis angle and time to fusion. Patients were evaluated at three months, six months and one year post-surgery.

Results: At present 14 patients with a total of 19 levels have completed their one year follow-up. The patients had an average of 50.4 years (range 34–69), with ratio of male to female of 6:7. Lordosis angle improved significantly from a mean lordosis angle of 0.31 preoperatively to 4.75 degree postoperatively (p< 0.05). All the levels had fused at the 1 year follow up and there was no radiological evidence of sinkage of the cage.

Conclusion: Substitution of silicate ions into calcium phosphate ceramics has been shown to impart a negative surface charge, leading to greater protein absorption, increased osteoblast proliferation, and higher production of extracellular matrix. Our results show that Si-CaP has excellent clinical performance as a synthetic bone graft in anterior cervical discectomy and fusion. Postoperatively, patients demonstrate a good fusion with an excellent correction and maintenance of the lordosis angle.

Aim: To determine the incidence of adjacent level osteophytes in patients who have had anterior cervical fusion using an anterior cervical plate as compared to those who are fused without an anterior cervical plate.

Design: We retrospectively reviewed the lateral radiograms of sixty two patients who have had an anterior cervical fusion with a minimum follow up of twelve months.

Materials and methods: We looked for the development of adjacent level osteophytes in these patients at their final follow up, which was generally at the time radiological fusion. There were 27 patients in the first group who had an anterior cervical plate used to fix the vertebrae in addition to the Cervios cage, while the 35 patients in the second group in whom only a Rabea cage was used for the fusion. The mean follow-up was 20.6 months (range 12–48).

Results: 64.3% of the patients who had an anterior cervical plate developed adjacent level osteophytes while none of the patients who have had the fusion without the cage developed the osteophytes.

Conclusion: We found the patients who had an anterior cervical interbody fusion using a plate had a significant risk of developing adjacent level osteophytes while this is not seen in patients who do not have the plate for the fixation.

Weight gain is often reported by patients who succumb to impaired activity as a result of progressive osteoarthritis of the hip or knee. Optimistic views of weight loss after joint replacement are often held by patients. We studied the affect of lower limb arthroplasty on body weight.

We reviewed 144 patients having undergone hip and knee arthroplasty and were functionally well. Infected cases were excluded. Average age was 65 years and average follow up was 27 months. The Body Mass Index (BMI) was prospectively measured at follow up and compared to immediate pre-operative BMI.

Our findings demonstrated an average rise in BMI post-operatively which was statistically significant. A rise in post operative BMI was seen in patients who were obese to start with or those who had undergone a total hip replacement (statistically significant). Moderate rises were seen in patients who had underwent hip resurfacing procedures or those who were overweight preoperatively (p=0.06).

These findings are useful in informing patients of achievable expectations following joint replacement surgery and preoperative overweightness should be treated as a separate entity unrelated to co-existing joint degeneration.

Introduction: Osteoarhthritis is a degenerative disease affecting a large proportion of the population. Recently, there has been renewed interest in the use of neutraceuticals (such as glucosamine) for the treatment of symptomatic pain and pathology in arthritic joints. However, little research has been carried out to assess the biochemical mechanisms by which glucosamine imparts its effects on the disease process. Biochemically, an early change in the cartilage metabolism is a loss of the large aggregating proteoglycan, aggrecan. Functionally, this loss results in a decreased capacity for the tissue to sustain mechanical loading that leads to cartilage destruction and a painful joint. The enzymes responsible for the loss of aggrecan from the tissue are commonly referred to as the aggrecanases and are members of the ADAMTS family of enzymes. Degradation of aggrecan by the aggrecanases can be detected using a specific neoepitope monoclonal antibody BC-3 (1). Model systems using cartilage explant cultures that mimic the degradative processes seen in osteoarthritis have been developed in which cytokine such as IL-1 are used to initiate the catabolic processes leading to cartilage degradation.

Methods: Cartilage explant cultures (bovine) were established using published methodologies (1). Explants were then incubated in either DMEM, DMEM supplemented with a chemically modified glucosamine (0.5–15mM) or DMEM supplemented with glucosamine hydrochloride (0.5–15mM) for 1 hour. IL-1 (10ng/ml) was then added to half of the explant cultures in each experimental group. Cultures were maintained for 4 days in the experimental media after which media and explants were harvested for analysis. Glycosaminoglycan (GAG) concentrations of media samples and cartilage extracts were determined using the DMMB assay. RNA was extracted from cartilage explants and RT-PCR was performed using primers to cartilage matrix molecules, ADAMTS and MMPs. Western blot analysis was performed on the experimental media using MAb BC-3 to determine the presence of aggrecanase-generated aggrecan catabolites.

Results: Experiments show that glucosamine hydrochloride (0.5–15mM) was unable to inhibit the release of GAG from explant cultures induced by treatment with IL-1. However, explant cultures preincubated with 10–15mM chemically-modified glucosamine were able to inhibit the release of GAG induced by IL-1 to that of control culture levels. The decreased release of GAG corresponded to a decrease in the detection of aggrecanase-generated aggrecan catabolites as assessed by Western blotting with MAb BC-3.

Discussion: This data questions the effectiveness of glucosamine hydrochloride in the inhibition of biochemical mechanisms involved in the IL-1 induced degradation of aggrecan in articular cartilage. However, the data suggests a role for a chemically modified glucosamine in the IL-1 induced degradative pathways involved in the loss of aggrecan from cartilage. The use of glucosamine in the treatment of arthritic diseases is controversial, however, the modified form of glucosamine used in this study helps to support the potential use of the dietary ingestion of glucosamine and its beneficial effects in arthritis patients. 1. Hughes, C.E., et al. (1995). Biochem. Journal. 305, 799–80