Introduction:. The C-Stem in its design as a triple tapered stem, is the logical development of the original Charnley flat-back polished stem. The concept, design and the surgical technique cater for a limited slip of the stem within the cement mantle transferring the load more proximally.

Method: Five thousand two hundred and thirty three primary procedures using a C-stem have been carried out since 1993. We reviewed all 621 cases that had their total hip arthroplasty before 1998.

Results:. Sixty nine patients (70 hips) had died and 106 hips had not reached a ten-year clinical and radiological follow-up and had not been revised. In 22 hips, the stem had been changed before the 10 year follow-up, with infection, dislocation and loosening of the cup being the reasons for revision. None of the stems were loose.

The remaining 423 hips had a mean follow-up of 11 years (range 10 – 15 years). There were 216 women and 173 men, and 34 patients had bilateral LFAs. The patients’ mean age at surgery was 53 years (range 16 – 83 years). Thirty eight hips had been revised at the time of review. The reasons for revision were infection in 5: dislocation in 2: loose cup in 28: wear in 2 and 1 for meralgia paresthetica where the stem was found to be well fixed. In 1 case which had not been revised there was radiological loosening of the stem in a patient with Gaucher’s disease.

Discussion: With only 1 stem radiologically loose and no revisions for stem loosening the clinical results are very encouraging and they support the concept of the Charnley cemented low friction arthroplasty, but place a demand on the understanding of the technique and its execution at surgery.

Aim: To identify the microbiology of infected knee arthroplasty, emerging patterns of resistance over the last decade, and suggest appropriate empirical treatment.

Methods: A retrospective analysis was conducted of 121 patients with microbiologically proven infection, who underwent revision TKA between 1994–2008. The causative organism was identified from microbiological samples and the corresponding sensitivities recorded. The data was then collated to determine the most common causative organisms, changing patterns of antibiotic resistance over the time frame, and the antibiotics currently most effective at treating deep infection. A theoretical model combining gentamicin with other antibiotics was used to determine the most effective antibiotics for use as empirical treatments.

Results: Coagulase negative Staphylococcus (CNS) was the most common causative organism (49%). Staphylococcus aureus (SA) accounted for 13% of cases. The prevalence of CNS appears to be increasing, while that of SA and other organisms is decreasing. Vancomycin and teicoplanin were the most effective antibiotics with overall sensitivity rates of 100% and 96% respectively. Levels of resistance were significantly higher among the antibiotics more commonly used in the community. Antimicrobial resistance was higher when the causative organism was CNS, suggesting that multi-drug resistant CNS is becoming a problem in knee arthroplasty. Our theoretical model showed that gentamicin combined with vancomycin would be the most effective empirical treatment.

Conclusion: Understanding the microbiology of deep infection of the knee allows surgeons to treat this complication as effectively as possible. Vancomycin and teicoplanin appear to be the most effective antimicrobials, with relative invulnerability to the development of resistance. Given the effectiveness of these antibiotics, the use of vancomycin in gentamicin bone cement, combined with IV teicoplanin potentially allows for infected knee arthoplasties to be treated with a one-stage procedure. The rational use of antibiotics may help limit the amount of antibiotic resistance which develops in the future.

Background: Since Sir John Charnley introduced bio-clean air operating techniques such as the “body exhausting” system and a bio-clean air operating theatre to reduce the risk of infection 3), total hip replacement has become one of the safest and most successful procedures in orthopaedic surgery and has benefited numerous people suffering from arthritis all over the world. However, deep infection is still undoubtedly one of the most serious complications after total hip arthroplasty (THA). It is still controversial whether one or two stage revision should be indicated for deeply infected hip replacement.

Purpose: The aim of this study was to identify the influential factors in one stage revision THA for deep infection with a long-term follow-up.

Methods: One stage revision THA for deep infection was carried out in 273 joints on 262 patients by the senior author between 1974 and 2000. All infected hip replacements were primarily treated with one stage revision THA regardless of micro organisms at the authors’ unit as far as sufficient bone stock for socket fixation was available in the acetabulum. This study included 162 revisions in 154 patients for which a minimum follow-up of five years (range 5 to 28 years; average 12.3 years) had been done. Fifty-two cases (32.1 %) had had discharging sinus by the time of revision surgery for infection.

Results: One hundred and thirty eight (85.2 %) hips were free of infection at the time of the latest follow-up. Twenty cases (12.3 %) had reoperation for recurrent infection. Four hips (2.5 %) maintained their implants with the evidence of infection. Twenty-two cases (13.6 %) showed radiological loosening. Thirteen cases (8.0 %) were revised again for reasons other than infection (12 for aseptic loosening and one for dislocation). Bone stock did not have significant influence on infection control while it did affect mechanical outcome. The cement-bone interface was an affecting factor for not only the mechanical survival of implants but also the cure of infection. Neither discharging sinus nor gram-negative microorganism was considered as a contraindication.

Conclusion: This study presented the longest follow-up with a large number of cases in revision THA for deep infection. The results suggested that shielding medullary space with antibiotic-loaded cement was important for treatment of infected THA.

Introduction: Hip resurfacing arthroplasty is increasing in popularity, particularly in young and active patients. One unique advantage is retention of upper femoral bone stock with the hypothesis of easy revision should the resurfacing fail. The pupose of this study was to document the complexity or otherwise of our early experience with failed hip resurfacing.

Methods: We retrospectively reviewed all the patients who had revision surgery for failed hip resurfacing arthroplasty at our institution.

Results: Eleven patients with mean age of 52.8 years underwent revision of resurfacing at a mean time of 21.2 months following primary surgery. Revision was performed for deep infection in 4, cup loosening in 4 and 1 patient each for femoral neck fracture, avascular necrosis, and femoral loosening. For the 4 patients with cup loosening, the acetabular component was revised in 3 using a dysplasia Birmingham cup while 1 patient had both components revised. Of the 4 patients with deep infection, 3 had both components revised as one-stage revision with cemented components and 1 patient had a pseudarthosis. For the 3 cases with femoral loosening, neck fracture or avascular necrosis only the femoral component was revised using a cemented stem. Bone grafting was performed in 1 patient who had revision for loosening of acetabular cup with protrusio.

Conclusion: Acetabular failure appears to be equally common as femoral failure in resurfacing arthroplasty. Revision of both aseptic and septic failure appears to be relatively straightforward with primary implants used in all cases.

Introduction: This study investigates whether the choose and book system satisfies the priorities of the local community and considers its implications for local elective primary lower limb arthroplasty.

Patients are offered a choice of 4 hospitals and time and date of outpatient appointment on referral from their GP practice. Research revealed that people want choice. Can popular centres still provide a service for the local population? What are the priorities of the local population when choosing a healthcare provider?

Method: A qualitative questionnaire was given to 100 people from the local community who were referred from their GP for a primary lower limb arthroplasty. This assessed patient’s opinions and priorities.

Results: 98% of patients wanted to choose their healthcare provider, 88% would not be content in any hospital other than their first choice

94% would not change hospitals if offered a shorter waiting time

Discussion: This study clearly indicates the local community want choice on referral for primary arthroplasty, but where they are operated is more important than when. The clinical quality of the provider is more important than the waiting time.

The government state patients want to choose the time and date of their first clinic appointment, however the majority of our population don’t.

The current ‘Choose and Book’ system does not fulfil patient’s priorities.

Introduction: The success of impaction-grafting depends on mechanical stability and adequate bony incorporation of the graft. Full incorporation of this type of graft has been demonstrated histologically and depends on many factors including the biological activity of the graft. Bone morphogenic proteins (BMPs) are known to play a central role in bone formation and their presence reflects the biological activity of a graft material. The aim of this study was to determine the activity of fresh frozen femoral head (FFH) grafts by analysing BMP-7 release after milling and during strain imposed by the impaction process.

Methods: 10mm cancellous bone cubes were cut from 5 samples of FFH. The cubes were washed, centrifuged and washed again to remove the marrow contents. Specimens from each femoral head were allocated to five groups and subjected to strains of 0%, 20%, 40%, 60% and 80% with a material testing machine. The cubes were washed again and the wash fluid analysed for bmp-7 activity using a commercially available elisa kit. Additionally, samples of bone were taken after standard milling of FFH, washed and the fluid analysed for bmp-7 activity.

Results: bmp-7 activity was found to be present in all groups. Release of bmp-7 was found to increase with increasing strain in a linear relationship. At 80% strain the mean concentration of bmp-7 released (2.2 ng/g bone) was approximately double that released at 20% strain.

Discussion: activity of bmp-7 in FFH has not previously been demonstrated. This study shows that the freezing and storage of femoral heads allows some maintainance of biological activity. Furthermore we have shown that bmp-7 may be released from FFH cancellous bone in proportion to the strain applied to the bone. This may go some way to explaining the full bony incorporation often seen after impaction-grafting.

In order to investigate the osteoinductive properties of allograft used in impaction grafting and the effect of strain during impaction on these properties, we designed an in vitro experiment to measure strain-related release of bone morphogenetic protein-7 (BMP-7) from fresh-frozen femoral head allograft. A total of 40 10 mm cubes of cancellous bone were cut from ten samples of fresh-frozen femoral head. The marrow was removed from the cubes and the baseline concentrations of BMP-7 were measured. Specimens from each femoral head were allocated to four groups and subjected to different compressive strains with a material testing machine, after which BMP-7 activity was reassessed. It was present in all groups. There was a linear increase of 102.1 pg/g (95% confidence interval 68.6 to 135.6) BMP-7 for each 10% increase in strain. At 80% strain the mean concentration of BMP-7 released (830.3 pg/g bone) was approximately four times that released at 20% strain. Activity of BMP-7 in fresh-frozen allograft has not previously been demonstrated. This study shows that the freezing and storage of femoral heads allows some maintenance of biological activity, and that impaction grafting provides a source of osteoinductive bone for remodelling.

We have shown that BMP-7 is released from fresh-frozen femoral head cancellous bone in proportion to the strain applied to the bone. This suggests that the impaction process itself may contribute to the biological process of remodelling and bony incorporation.

We carried out a retrospective case-control study in 80 patients who underwent a revision total hip replacement. Group A (40 patients) received tranexamic acid and intra-operative cell salvage. Group B (40 patients) was a matched control group and did not receive this management. Each group was divided into four subgroups: revision of both components, revision of both components with bone grafting, revision of the acetabular component with or without bone graft, and revision of the femoral component with or without bone graft.

In group A the total number of units transfused was 52, compared with 139 in group B, representing a reduction in blood usage of 62.5%. The mean amount of blood transfused from cell salvage in each group was 858 ml (113 to 2100), 477 ml (0 to 2680), 228 ml (75 to 315) and 464 ml (120 to 1125), respectively. There was a significant difference in the amount of blood returned between the groups (p < 0.0001).

In group A, 22 patients needed transfusion and in group B, 37 (p < 0.0001). A cost analysis calculation showed a total revenue saving of £70 000 and a potential saving throughout our facility of £318 288 per year.

Our results show that a significant reduction in blood transfusion can be made using combined cell salvage and tranexamic acid in revision surgery of the hip.

Factors influencing the results of revised cemented sockets with bone grafting have been studied in 249 cases.

Freeze-dried allografts in 77 and fresh frozen in 172 cases have been used. The average follow-up was 8 years 11 months for the freeze-dried group and 2 years 11 months for the fresh frozen cases. There were 13 postoperative dislocations, 20 TNU, 4 thromboembolic complications, 4 delayed wound healing and 2 intraoperative fractures of the acetabulum. There have been 11 re-revisions: 8 for aseptic loosening, 2 for dislocation and 1 for infection. Radiographic evidence of loosening was seen in another 38 cases.

The acetabular bone stock at the time of revision and initial stability of socket fixation had a significant influence on the outcome. Direction of socket migration before surgery appeared to predict risk of failure. The primary pathology, type of bone graft and grafting technique also had an effect.

We previously reported the result of 45 Charnley LFA’s with femoral head autograft for Developmental Dysplasia of the hip with a minimum follow-up of ten years.

After an average follow-up of eleven years there was no revision. One socket migrated and four sockets were fully demarcated.

To assess our long-term results we reviewed the clinical and radiological findings in the same group of patients that had been studied previously.

To date 5 patients died from causes unrelated to the hip replacement and were excluded from the final radiological analysis. 40 Charnley LFA’s have been followed-up regularly.

The average follow-up is now 17 years 1 month / range: 15–21 years/. Three sockets have been revised: two for aseptic loosening and one for infection. Radiographic assessment showed that three sockets migrated and four had full demarcation.

Demarcation at the cement-bone interface of the socket was rare in zone one but was common in zone two.

We concluded that sound fixation of the autograft and orientations of the acetabular component are essential. We recommend that solid bone graft should be combined with impaction bone grafting in dysplastic cases. We also observed that bone grafting at primary surgery gives better chances for component fixation at the time of revision.

Background: Dislocation after total hip replacement (THR) is a significant concern with the increased number of THR carried out all over the world, although there has been a substantial lack of information regarding revision THR for instability in literature.

Purpose: The purpose of this study was to evaluate the effectiveness of operative treatment for recurrent dislocation after THR.

Material and methods: One hundred and eleven cases were treated operatively for recurrent dislocation after THR by a senior author (BMW). Group A; 104 cases were operated with change of either or both of components, a socket and a stem. Twenty-two mm head was used in 90 cases (A-1), 32 mm head in twelve (A-2), and 36 mm head in two (A-3). Group B; only modular head was changed in one case. Group C; augmentation device was applied on a cup in six cases. The average follow-up period was 6.2 years (range, 1 to 21 years).

Results: Group A-1; twelve cases (13%) required further operations for instability (N=90). Group A-2; one case (8.3%) was converted to Girdle-Stone for recurrent dislocation (N=12). Group A-3; one of them was revised for periprosthetic fracture (N=2). Group B; the case survived at the follow-up of 3.3 years (N=1). Group C; two cases (33%) were revised for dislocation (N=6).

Conclusion: We reported the largest series of revision THR for recurrent dislocation by a single surgeon with a considerable length of follow-up periods. Revision THR with change of components was an effective treatment for recurrent dislocation after THR.

A retrospective review of MRSA screening showed that of a total of 8911 patients screened pre-operatively between May 1996 and February 2001, 83 (0.9%) had MRSA isolated from one source or another. During the same period, 115 (13.6%) of 844 positive tissue samples taken during surgery grew Staphylococcus aureus. Of these only 1 (0.01%) was reported to be methicillin-resistant (MRSA). However, a total of 366 (43.4%) isolates from tissue samples were reported as coagulase-negative staphylococci (C-NS). Of these, 312 samples were tested for methicillin sensitivity, of which 172 (55.1%) were found to be resistant.

Staphylococcus epidermidis is the most prevalent and persistent species found on most skin and mucous membranes, constituting 65% to 90% of all staphylococci. Most isolates in tissue samples were found to be methicillin-resistant coagulase-negative staphylococcus (55.1%). Hence, it may be appropriate to undertake screening for methicillin-resistant Staphylococcus epidermidis in addition to that for MRSA.

Tumour necrosis factor-alpha is a proinflammatory cytokine that has been implicated in the propagation of inflammatory responses to bacterial infection and wear debris particles around loosened total hip replacements (THR). Individual TNF responses to such stimuli may be dictated by genetic variation. Single nucleotide polymorphisms (SNPs) at several loci within the TNF gene are associated with disease severity and susceptibility in a number of inflammatory conditions, but only a few SNPs have been screened in any one study.

14 SNPs have been identified within the TNF gene. Our unit has previously demonstrated that 5 SNPs are monomorphic in a sample group of UK Caucasians. We performed a case control study of the remaining 9 polymorphic positions (−1031, −863, −857, −376, −308, −238, +489, +851 and +1304) for possible association with deep sepsis or aseptic loosening.

All patients included in the study were Caucasian and had had a cemented Charnley THR and polyethylene cup. Cases consisted of 44 patients with early aseptic loosening (defined as that occurring within 6 years of implantation and findings at revision surgery or by the criteria of Hodgkinson et al for the acetabulum and Harris for the femoral stem) and 30 patients with microbiological evidence at surgery of deep infection. Controls consisted of 85 THRs that had remained clinically asymptomatic for over 10 years and demonstrated no radiographic features of aseptic loosening or ‘at risk’ signs as described by Wroblewski et al. DNA was extracted from venous blood and genotyped by Snapshot assay.

Genotype and allele frequencies for all SNPs were in Hardy-Weinberg equilibrium between THR controls and a random sample of UK Caucasians. The most significant associations were between the −238A (p< 0.05) and −863T (p< 0.05) alleles and aseptic loosening. A trend towards association was found between the −863A SNP and deep infection (p=0.80). The −238 A/G and −863 G/T genotypes were associated with deep infection (p< 0.05). No other significant associations were found.

Genetic polymorphism of TNF appears to play a significant role in THR aseptic loosening and possibly in deep infection. SNP markers may serve as predictors of implant survival and response to therapy such as anti-TNF treatment.

The metabolic response of trauma may mimic infection and the reliability of serological parameters for diagnosing infection may be questionable. We prospectively assessed the changes in the acute inflammatory markers, febrile response and the immune profiles cytokine activation and collagen markers of 101 patients following primary hip arthroplasty and their association with infection.

Method: The clinical outcome of 101 patients was monitored. Serological analysis was performed pre-operatively and on the second and 8th post-operative day as well as in an out patient clinic 6 weeks following surgery. The serological markers included total white blood cell count along with T and B lymphocyte function. Levels of CD4, CD8 and CD56 were analysed for T helper, T Cytotoxic cell and Natural Killer cell activity. Inflammatory makers included plasma viscosity and CRP. Cytokine assays included IL-1, IL-6, IL-10 and TNF. Collagen markers included P1CP and P1NP as markers of Type I and Type III collagen synthesis. Serological titers of Staph. Aureus and Staph. Epidermis were performed pre-operatively and on day 8 and week 6 following surgery.

Results: Post-operative complications included 19 UTI, 11 chest infections and three URTI and six a confirmed deep vein thrombosis. Wound complications included 10 patients with wound erythema and 4 patients had pus discharge. 20 patients had elevated ASO titers and 19 patients had raised Staph. Epidermis titers.

Statistical comparison of WBC, Plasma viscosity, temperature profiles and T helper,

T cytotoxic cell and NK cell assays is not different between patients with and without systemic infection or raised titres of Staph. Aureus or Staph. Epidermis. Collagen markers were significantly higher in wound complications.

Conclusion: The acute phase responses following surgery and metabolic response to trauma obscures the changes seen in infective complications up to six weeks post-operatively. The use of serological parameters that are components of the acute phase response of surgery does not allow differentiation of infection from normal physiological changes.

Blood transfusion is associated with an increased incidence of post-operative nosocomial infections following surgery. In a prospective study we evaluated the association of blood transfusion and the changes in the immune status with the incidence of infection in the post-operative period following primary hip arthroplasty and subsequently for two years following surgery

Method: Prospective analysis of 100 patients undergoing primary total hip replacement. 25 patients received predonated autologus blood transfusions, 26 received SAGM whole blood, 23 received leukocyte depleted blood and 26 did not require a transfusion.

T-helper cell, cytotoxic T cell and NK cell activity was recorded using a Beckton Dickson flow cytometer and assays of Plasma viscosity, CRP, Staph. Epidermis and ASO titres were analysed. All infections were recorded for 2 years following surgery.

Results: he incidence of confirmed or suspected nosocomial infections following hip replacement was the same in non transfused patients as those receiving predonated autologus blood (19%). The incidence of nosocomial infection in patients receiving leukocyte depleted blood was 32% and 42% in those receiving a SAGM blood transfusion. ASO titres were raised in 16.9% of the patients on day 8 following surgery and Staph. Epidermis assays were raised in 20.2% of the patients however the frequency was unrelated to the type of blood transfusion.

The incidence of nosocomial infections was reflected by a greater reduction in NK activity and CD4: CD8 ratio following surgery in patients receiving SAGM blood transfusion.

Conclusion: Homologus blood transfusion may produce an immune compromise in patients, which is still detectable at 6 weeks following surgery. This is clinically reflected by a higher incidence of systemic infections in the postoperative period.

Homologus blood should be used judiciously in joint arthroplasty with a preference to either leukocyte depleted blood or predonated autologus blood.

Pyrexia in the post-operative setting has often been associated with a possible systemic or wound infection. We assessed whether there is any justification for our concern regarding post-operative pyrexia following hip arthroplasty and subsequent deep prosthetic infection.

Method:

Study 1

An assessment of the clinical outcome of 97 sequential patients who underwent 103 primary hip arthroplasty for primary osteoarthritis replacements. Daily temperature and systemic complications in the post-operative period were recorded. Clinical outcome was measured using an Oxford hip questionnaire.

Patients had a mean follow-up of 5.2 years (range 3.5–7.2years).

Study 2

A review of postoperative temperature records of 80 patients who had undergone primary total hip replacement. Thirty-one patients had required revision surgery at a mean time interval of 37.2 months (range 5–74 months) for confirmed deep prosthetic infection. The remaining Forty-nine patients were asymptomatic at a mean follow-up of 31.5 months.

Results:

Study 1

Post-operative pyrexia of 38 degrees Celsius was present in 51% of patient’s undergoing primary hip replacement in the first post-operative week but in 21.1% no etiological cause could be identified. Clinical outcome measured by an oxford hip questionnaire was not influenced by the post-operative temperature pattern.

Study 2

The mean peak temperature on the first post-operative day was significantly lower in patients with deep prosthetic infection then patients with a clinically normal outcome (p=0.01).

Conclusion: Post-operative pyrexia is clearly not uncommon following primary arthroplasty and its presence should not be regarded as detrimental. Pyrexia in the post-operative setting is a component of the acute phase response to trauma and study 2 demonstrates patients who develop a low-grade infection following arthroplasty may have diminished febrile response to surgical trauma.

Bone cement with an antibiotic additive is currently widely available, gentamicin being the most common type. However, the high resistance of such organisms as staphylococci to gentamicin has popularised the practice of adding additional antibiotic powders to the cement mix.

This study aims to quantify the effects of adding 1g active of seven antibiotics on the viscoelastic properties of the cement from mixing to set time using a robust rheometer, developed at the University of Leeds. CMW1 Radiopaque cement was the base cement selected for its widespread familiarity.

Viscosity and elasticity were recorded at two rates of shear until the cements set. Viscosity was found to decrease with shear rate, but the cements were found to have a significant elastic component that greatly increased with shear rate. This indicates that for maximum cement penetration, maintained pressure would be more effective than “hammering”.

It should be noted that the effects described above are small compared to other theatre variables, especially temperature and humidity.

All surgical operations have the potential for contamination, and the equipment used can harbour bacteria. We collected samples from 100 elective primary hip and knee arthroplasties. These showed rates of contamination of 11.4% for the sucker tips, 14.5% for light handles, 9.4% for skin blades and 3.2% for the inside blades used during surgery; 28.7% of gloves used for preparation were also contaminated. Of the samples taken from the collection bags used during hip arthroplasty, 20% grew bacteria, which represents a significant microbial reservoir. Also, 17% of theatre gowns were contaminated at the end of the operation. Contamination was found in 10% of the needles used during closure of the fascia. Overall, 76% of the organisms grown were coagulase-negative staphylococcus. A total of 63% of operations showed contamination in the field of operation. Some changes in practice are suggested. Follow-up for a minimum of two years revealed one deep infection but the organism was not identified as a contaminant. These data provide a baseline for studying the bacteriology of the surgery of revision arthroplasty.