Aims

We compared the risks of re-revision and mortality between two-stage and single-stage revision surgeries among patients with infected primary hip arthroplasty.

Aims

With increasing burden of revision hip arthroplasty (THA), one of the major challenges is the management of proximal femoral bone loss associated with previous multiple surgeries. Proximal femoral arthroplasty (PFA) has already been popularized for tumour surgeries. Our aim was to describe the outcome of using PFA in these demanding non-neoplastic cases.

Periprosthetic joint infections (PJIs) are uncommon but are devastating complications of total knee replacement (TKR). We analysed the risk factors of revision for PJI following primary TKR and their association with PJI at different post-operative periods. Primary TKRs and subsequent revision surgeries performed for PJI from 2003–2014 were identified from the National Joint Registry (NJR). Multilevel piece-wise exponential non-proportional hazards models were used to estimate the effect of the investigated factors at different post-operative periods. Patient, perioperative and healthcare system characteristics were investigated and data from the Hospital Episode Statistics for England were linked to obtain information on specific comorbidities. The index TKRs consisted of 679,010 primaries with 3,659 subsequently revised for PJI, 7% within 3 months, 6% between 3–6months, 17% between 6–12months, 27% between 1–2years and 43% ≥2 years from the index procedure. Risk factors for revision for PJI included male sex, high BMI, high ASA grade and young age. Patients with chronic pulmonary disease, diabetes and liver disease had higher risk of revision for PJI, as had patients who had a primary TKR for an indication of trauma or inflammatory arthropathy. Surgical procedure, fixation method, constraint and bearing type influenced the risk of revision for PJI. Their effects were period-specific. No or small associations were found with the operating surgeon grade, surgical volume and hospital surgical volume. These findings from the world's largest joint replacement registry show a more complex picture than the meta-analyses published to date with specific time-dependent effects for the identified risk factors.

Introduction

Prosthetic joint infection (PJI) is an uncommon but serious complication of hip replacement.

A recent systematic review of patient risk factors for PJI identified male gender, smoking status, increasing BMI, steroid use, previous joint surgery and comorbidities of diabetes, rheumatoid arthritis and depression as risk factors for developing PJI. Limitations of the current literature include the short term follow up of most published studies.

We investigated the role of patient, surgical and healthcare factors on the risk of revision of a primary hip replacement for PJI at different time-points in the post-operative follow-up. It is important that those risk factors are identified so that patients can be appropriately counselled according to their individual risk profile prior to surgery and modifiable factors can be addressed to reduce the risk of PJI at an individual and healthcare system level.

Aims

The aim of this study was to determine whether patients with metal-on-metal (MoM) arthroplasties of the hip have an increased risk of cardiac failure compared with those with alternative types of arthroplasties (non-MoM).

With increasing burden of revision hip arthroplasty, one of the major challenge is the management of bone loss associated with previous multiple surgeries. Proximal femoral replacement (PFR) has already been popularised for tumour surgeries. The inherent advantages of PFR over allograft –prosthesis system, which is the other option for addressing severe bone loss include, early weight bearing and avoidance of non-union and disease transmission. Our study explores PFR as a possible solution for the management of complex hip revisions. Thirty consecutive hips (29 patients) that underwent PFR between January 2009 and December 2015 were reviewed retrospectively for their clinical and radiological outcomes. The Stanmore METS system was used in all these patients.

Mean age at the index surgery (PFR) was 72.69 years (range 50–89) with number of previous hip arthroplasties ranging from 1–5. At mean follow up of 32.27 months, there were no peri-prosthetic fractures and no mechanical failure of the implants. Clearance of infection was achieved in 80% of cases. There was 1 early failure due to intra-operative perforation of femoral canal needing further revision and two were revised for deep infection. Instability was noted in 26.7% (8) of the hips, of which, 87.5% (7) needed further revision with constrained sockets. Out of these 8 hips with instability, 5 had pre-operative infection. Deep infection was noted in 20% (6) of the hips, of which, 5 were primarily revised with PFR for septic loosening. However, further surgeries were essential for only 3 patients. One patient has symptomatic aseptic acetabular loosening and 1 had asymptomatic progressive femoral side loosening (lost to follow up).

Severe proximal femoral bone loss in complex revision arthroplasties has necessitated the use of PFR prosthesis. Our study supports the fact that PFR is probably a mechanically viable option for complex revisions. Significant numbers of dislocations and infections could be attributed to the poor soft tissue envelope around the hip. Further surgical techniques in the form use of dual mobility cups and silver coated PFR implants need to be explored.

Background

One of the major concerns of hinge knees have been reported in literature is mechanical failure. Failure in the form of component fracture (2–10%) and hinge dislocation/ failure are worrisome. In addition, higher risk of aseptic loosening with hinge knee prosthesis has been attributed to stress transfer at bone cement interface.

Prosthetic joint infection (PJI) is an uncommon but serious complication of hip and knee replacement. We investigated the rates of revision surgery for the treatment of PJI following primary and revision hip and knee replacement, explored time trends, and estimated the overall surgical burden created by PJI.

We analysed the National Joint Registry for England and Wales for revision hip and knee replacements performed for a diagnosis of PJI and their index procedures from 2003–2014. The index hip replacements consisted of 623,253 primary and 63,222 aseptic revision hip replacements with 7,642 revisions subsequently performed for PJI; for knee replacements the figures were 679,010 primary and 33,920 aseptic revision knee replacements with 8,031 revisions subsequently performed for PJI. Cumulative incidence functions, prevalence rates and the burden of PJI in terms of total procedures performed as a result of PJI were calculated.

Revision rates for PJI equated to 43 out of every 10,000 primary hip replacements (2,705/623,253), i.e. 0.43%(95%CI 0.42–0.45), subsequently being revised due to PJI. Around 158 out of every 10,000 aseptic revision hip replacements performed were subsequently revised for PJI (997/63,222), i.e. 1.58%(1.48–1.67). For knees, the respective rates were 0.54%(0.52–0.56) for primary replacements, i.e. 54 out of every 10,000 primary replacements performed (3,659/679,010) and 2.11%(1.96–2.23) for aseptic revision replacements, i.e. 211 out of every 10,000 aseptic revision replacements performed (717/33,920). Between 2005 and 2013, the risk of revision for PJI in the 3 months following primary hip replacement rose by 2.29 fold (1.28–4.08) and after aseptic revision by 3.00 fold (1.06–8.51); for knees, it rose by 2.46 fold (1.15–5.25) after primary replacement and 7.47 fold (1.00–56.12) after aseptic revision. The rates of revision for PJI performed at any time beyond 3 months from the index surgery remained stable or decreased over time.

From a patient perspective, after accounting for the competing risk of revision for an aseptic indication and death, the 10-year cumulative incidence of revision hip replacement for PJI was 0.62%(95%CI 0.59–0.65) following primary and 2.25%(2.08–2.43) following aseptic revision; for knees, the figures were 0.75%(0.72–0.78) following primary replacement and 3.13%(2.81–3.49) following aseptic revision.

At a health service level, the absolute number of procedures performed as a consequence of hip PJI increased from 387 in 2005 to 1,013 in 2014, i.e. a relative increase of 2.6 fold. While 70% of those revisions were two-stage, the use of single stage revision increased from 17.6% in 2005 to 38.5% in 2014. For knees, the burden of PJI increased by 2.8 fold between 2005 and 2014. Overall, 74% of revisions were two-stage with an increase in use of single stage from 10.0% in 2005 to 29.0% in 2014.

Although the risk of revision due to PJI following hip or knee replacement is low, it is rising. Given the burden and costs associated with performing revision joint replacement for prosthetic joint infection and the predicted increased incidence of both primary and revision hip replacement, this has substantial implications for service delivery.

Distal femoral replacement is an operation long considered as salvage operation for neoplastic conditions. Outcomes of this procedure for difficult knee revisions with bone loss of distal femur have been sparsely reported.

We present the early results of complex revision knee arthroplasty using distal femoral replacement implant, performed for severe osteolysis and bone loss.

Retrospective review of clinic and radiological results of 25 consecutive patients operated at single centre between January 2010 and December 2014. All patients had single type of implant. All data was collected till the latest follow up. Re-revision for any reason was considered as primary end point.

Mean age at surgery was 72.2 years (range 51 – 85 years). Average number of previous knee replacements was 2.28 (range 1 to 6). Most common indications were infection, aseptic loosening and peri-prosthetic fracture. Average follow up was 24.5 months (range: 3–63 months). 1 patient died 8 months post-op due to unrelated reasons. Re-revision rate was 2/25 (8%) during this period. One was re-revised for aseptic loosening and one was revised for peri-prosthetic fracture of femur. Two other peri-prosthetic fractures were managed by open reduction and internal fixation. All 3 peri-prosthetic fractures occurred with low energy trauma.

It is noteworthy that there was no hinge or mechanical failures of the implant. Peri-prosthetic fracture in 12% of patients in this series is of concern. There are no similar studies to compare this data with. The length of the stem, type of fixation of the stem, weight of the distal femoral component of implant can be postulated as factors contributing to risk of peri-prosthetic fracture.

Introduction

A recent paper suggested implanting an uncemented acetabular shell which is 6mm or greater than the native femoral head in total hip arthroplasty (THA) significantly increased the risk of postoperative pain. We retrospectively analyzed 265 Delta ceramic-on-ceramic (DCoC) THA comparing the native femoral head size to the implanted shell and reviewing if the patient suffered with post-operative pain (POP).

Background

Current analysis of unicondylar knee replacements (UKR) by national registries is based on the pooled results of medial and lateral implants. Using data from the National Joint Registry for England and Wales (NJR) we aimed to determine the proportion of lateral UKR implanted, their survival and reason for failure in comparison to medial UKR.

Introduction

Following in-depth analysis of the market leading brand combinations in which we identified implant influences on risk of revision, we compared revision in patients implanted with different categories of hip replacement in order to find implant with the lowest revision risk, once known flawed options were removed.

Current analysis of unicondylar knee replacements (UKRs) by national registries is based on the pooled results of medial and lateral implants. Consequently, little is known about the differential performance of medial and lateral replacements and the influence of each implant type within these pooled analyses. Using data from the National Joint Registry for England and Wales (NJR) we aimed to determine the proportion of UKRs implanted on the lateral side of the knee, and their survival and reason for failure compared with medial UKRs. By combining information on the side of operation with component details held on the NJR, we were able to determine implant laterality (medial versus lateral) for 32 847 of the 35 624 unicondylar replacements (92%) registered before December 2010. Of these, 2052 (6%) were inserted on the lateral side of the knee. The rates of survival at five years were 93.1% (95% confidence interval (CI) 92.7 to 93.5) for medial and 93.0% (95% CI 91.1 to 94.9) for lateral UKRs (p = 0.49). The rates of failure remained equivalent after adjusting for patient age, gender, American Society of Anesthesiologists (ASA) grade, indication for surgery and implant design using Cox’s proportional hazards method (hazard ratio for lateral relative to medial replacement = 0.88 (95% CI 0.69 to 1.13); p = 0.32). Aseptic loosening/lysis and unexplained pain were the main reasons for revision in both groups, although the reasons did vary depending on whether a mobile- or a fixed-bearing design was used. At a maximum of eight years the mid-term survival rates of medial and lateral UKRs are similar.

Introduction

We aim to assess the functional outcome, patient perceived satisfaction and implant survival at a mean follow up of 13[10–16] years following revision knee replacement.

Introduction

We aim to assess the functional outcome, patient satisfaction and implant survival at a mean follow up of 13[10–16] years following revision for infected total knee replacement.

SUMMARY

We report a prospective study of clinical data collected pre, intra and post operation to remove both cup and head components of 118 failed, current generation metal on metal (MOM) hips. Whilst component position was important, the majority were unexplained failures and of these the majority (63%) had cup inclination angles of less than 55 degrees. Poor biocompatibility of the wear debris may explain many of the failures.

We have assessed the bone cuts achieved at surgery compared to the planned cuts produced during computer assisted surgery (CAS) using a CT free navigation system. In addition, two groups of matched patients were compared to assess the post-operative mechanical alignment achieved: 14 patients received a LCS total knee replacement (TKR) using the VectorVision module and 14 received a TKR using a conventional method of extramedullary alignment jigs The deviation in each plane (valgus-varus, flexion-extension and proximal-distal) was calculated.

For the tibia the mean deviation in the coronal plane was 0.21 degrees of Varus (SD = 1.37) and in the sagittal plane was 1.29 degrees of flexion (SD = 3.73) and 0.24 mm of resection distal to the anticipated cut (SD = 2.14). For the femur the mean deviation in the coronal plane was 0.88 degrees (SD = 2.2) of valgus and in the sagittal plane the mean deviation was 0.3 degrees (SD = 2.91) of extension. In the transverse plane there was a mean deviation of 0.07 degrees (SD = 1.57) of external rotation. There was mean deviation of 2.33 mm of proximal resection (SD = 2.9) and 1.05 mm of anterior shift (SD = 2.81).

On comparing the two groups, no statistically significant differences were found for the angles between the femoral component and the femoral mechanical axis, the tibial component and the tibial mechanical axis, the femoral and tibial mechanical axis and the femoral and tibial anatomical axis.

We have demonstrated variation in the true bone cuts obtained using computer assisted surgery from those suggested by the software and have not demonstrated significant improvement in post-operative alignment. Justification for the extra cost, time and morbidity associated with this technology must be provided in the form of improved clinical outcomes in the future.

Introduction: The London Implant Retrieval Centre (LIRC) was founded to investigate the high incidence of unexplained failures of Metal-on-Metal (MoM) hips. A multidisciplinary team analyse the failed hips, investigations include CT and MRI scans, blood and synovial fluid tests, wear measurements, X-rays and clinical data from the explanting surgeons.

Wear measurements of 100 explanted hips have been carried out on a Taylor Hobson 365 Roundness Machine using the LIRC Wear Protocol. It was found that 50% of explanted cups were wearing less than 5 μm/year and 60% of components were wearing less than 10 μm/year. Wear tests on hip joint simulators predict wear rates between 2 and 8 μm/year. However, 6% of cups are wearing faster than 100 μm/year, with 16% of cups have wear patches deeper than 100 μm and that 4% have a wear patch deeper than 300 μm.

Discussion: This paper considers the common characteristics of components in this very high wearing category. Engineering parameters such as head/cup clearance, surface finish, form errors and head cup contact conditions are investigated. This is correlated with clinical data and other results from the LIRC.

Cup position is an important factor, all of the high wearing components are outside the Lewinick’s Box, however it is shown that mal position is does not always lead to extreme wear. Further analysis is taking place to calculate the size of the contact patch between head and cup (based on patient data and biomechanics) and the proximity of the contact patch to the edge of the cup.

Conclusion: The study of explanted components shows that 6% exhibit extreme wear, and although several “risk” factors can be identified, it is not clear why only a proportion of these components show extremely high wear rates. This is the subject of current investigation.

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 commonly used in the community. Antimicrobial resistance was higher when the causative organism was CNS, suggesting that MRSE 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 tei-coplanin 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.

‘Force-closed’, tapered, polished, collar-less stems, (e.g. C-stem, Exeter), are designed to subside in response to expansion of the cement/bone complex over time. Above a certain threshold, distal migration may predict medium-to-long-term failure of ‘shape-closed’ stems. However, no such threshold exists for ‘force-closed’ stems, and these may continue to migrate after 3 years. We believe that the tendency towards stabilisation 2–3 years postoperatively, could be the best predictor of good long-term performance.

Twenty OA patients (12F, mean age 66.6 years) were recruited for primary hip replacement with beaded C-stem femoral components. Tantalum marker beads were injected into the proximal femur, and stems were inserted using CMW1 cement and the latest generation cementing technique via a posterior approach: 17, and a lateral, trochanteric approach: 3. RSA X-ray examinations were performed at 1 week, 6 weeks, and at 3, 6, 12, 24 and 36 months postoperatively. The UmRSA system was used to measure and analyse the radiographs. At 36M the mean stem centroid subsidence was 1.05 mm and had levelled off to a low rate. The mean internal rotation of 2.5° at 36M had not significantly changed during the final year (p = 0.08).

At 36M the mean posterior migration of the stem centroid was 0.54 mm (rate of 0.11 mm/y) and posterior migration of the femoral head was 1.66 mm (rate of 0.25 mm/y).

At 36M the mean subsidence rate was very low and the mean posterior migration was about one third of that reported for another RSA study of the C-stem. Although the mean internal rotation was greater than that reported for the Exeter stem, there was no significant change during the final year. These low rates of migration at 3 years are consistent with the good results found in clinical studies of this femoral component.

Introduction: Leg length discrepancy (LLD) following total hip arthroplasty (THA) can lead to disappointed patients, increased dislocation, increased wear and suboptimal function. It is one of the commonest reasons for litigation following THA in the United States. The purpose of this study was to radiologically and functionally assess the efficacy of a simple technique for intra-operative leg length assessment during THA via a posterior approach.

Materials & Methods: This technique was undertaken in 50 consecutive THAs. The pre-and 3 month postoperative LLD was measured on standing AP pelvis radiographs. The results were compared with 50 THAs performed by the same surgeons without using the technique. Pre-and post-operative OHS and UCLA scores were recorded in both groups.

Results: In the control group the mean pre- and postoperative LLD was 9.38 mm and 7.75mm respectively. In the new technique group the mean pre-operative LLD was 11.37 and the post-operative LLD was 1.70mm. The final LLD was significantly less in the new technique group (p< 0.001). Fifteen patients in the control group and three patients in the new technique group had post–operative lengthening. Oxford Hip and UCLA score improvement in new technique group was greater than in the control group (p< 0.05).

Discussion: The technique we introduced to assess leg length intra-operatively has shown to be safe, reliable and accurate. We have nonetheless demonstrated much greater accuracy at providing equal leg lengths and improved functional outcome using this new technique.

Introduction: The clinical results of the modular Charnley Elite total hip system have been the subject of some interest in recent years. Some studies have shown significant subsidence and rotational instability in some stems when used with low-viscosity cement. These unstable stems have been shown to fail early. This purpose of this study is to demonstrate our conflicting clinical results.

Materials and Methods: 616 modular Charnley Elite total hip arthroplasties were inserted between 1995 and 2002 at Wrightington Hospital, which is a tertiary referral centre and centre of excellence for joint replacement in United Kingdom. Both Consultants and trainees performed operations and a variety of surgical approaches were used. Normal viscosity bone cement was used in all patients. All patients were followed up prospectively.

Results: At mean follow-up of 8 years (range 5–12), 471 hips were available for review. 87 patients had died and 12 were lost to follow-up. 2.7% (13 cases) of femoral components and 2.9% (14 cases) of acetabular components had been revised for aseptic loosening. 10 hips (2.1%) underwent revision for deep infection and 2 (0.04%) for recurrent dislocation. The overall survival with aseptic loosening as an end point was 97% and for revision for any reason was 94.5%.

Conclusion: Our results show acceptable clinical survivor-ship for this implant when used with standard viscosity cement. This contrasts with the lower survivorship rates published by other centres. Our result should reassure patients and surgeons alike that this prosthesis can be associated with acceptable results in the medium term.

Introduction: Total hip replacement (THR) in young patients is a controversial subject due to high failure rates reported in the literature. The purpose of this study was to show our short term results of primary total hip replacement in patients younger than 30 years of age.

Methods: Patients who underwent THR prior to the age of 30 years between 1998 and 2007 were identified and records of all patients were reviewed together with the radiographs till the last follow up.

Results: Forty three THRs were performed on 36 patients with an average age of 24.4 years (range, 17–30) and an average follow up period of 47 months (range, 7–109 months). There were 5 cases of Juvenile chronic arthritis, 2 Rheumatoid arthritis, 11 DDH, 2 septic arthritis, 1 pseudoachondroplasia, 4 Perthes disease, 2 seronegative arthitides, 2 SUFE and 7 AVN [alcohol, leukaemia, fracture, SLE (2), mannosidosis, idiopathic].

Thirty cemented THRs and 13 hybrid THRs were performed through trochanteric osteotomy approach (23), posterior approach (17), Hardinge approach (2) and anterior approach (1). In the cemented group there were 3 cases of superficial wound discharges, 1 recurrent dislocation, 1 complete femoral nerve palsy, 2 cases of neuropraxia and 1 case with persistent hip pain but no cases of infection. In the hybrid group there was one case of partial femoral nerve palsy. None of the patients has undergone any revision surgery till the latest follow up. Radiologically only one case showed aseptic loosening in both femoral and acetabular components, which is not revised as the patient is asymptomatic.

Discussion: THR is an elegant procedure and should be certainly considered in young patients suffering with disabling arthritic conditions affecting the hip joint. Our results show that THR - both cemented and hybrid types - is a successful and durable treatment.

Introduction: The clinical results of the modular Charnley Elite total hip system have been the subject of some interest in recent years. Some studies have shown significant subsidence and rotational instability in stems when used with low-viscosity cement. These unstable stems have been shown to fail early. The purpose of this study is to demonstrate our conflicting clinical results.

Materials and Methods: 616 modular Charnley Elite total hip arthroplasties were inserted between 1995 and 2002 at Wrightington Hospital, which is a tertiary referral centre and centre of excellence for joint replacement in United Kingdom. Both Consultants and trainees performed operations and a variety of surgical approaches were used. Normal viscosity bone cement was used in all patients. All patients were followed up prospectively.

Results: At mean follow-up of 8 years (range 5–12), 471 hips were available for review. 87 patients had died and 12 were lost to follow-up. 2.7% (13 cases) of femoral components and 2.9% (14 cases) of acetabular components had been revised for aseptic loosening. 10 hips (2.1%) underwent revision for deep infection and 2 (0.04%) for recurrent dislocation. The overall survival with aseptic loosening as an end point was 97% and for revision for any reason was 94.5%.

Conclusion: Our results show acceptable clinical survivor-ship for this implant when used with standard viscosity cement. This contrasts with the lower survivorship rates published by other centres. Our result should reassure patients and surgeons alike that this prosthesis can be associated with acceptable results in the medium term.

Introduction: “Force-closed”, tapered, polished, collarless stems, (e.g. C-stem, Exeter), are designed to subside in response to a gradual expansion of the cement/bone complex.

Above a certain threshold, distal migration may predict medium-to-long-term failure of “shape-closed” (collared, textured) stems. However, no such threshold exists for “force-closed” stems, and these may continue to migrate after 3 years. We believe that the tendency towards stabilisation 2–3 years postoperatively could be the best predictor of good long-term performance.

Method: Twenty OA patients (12F, mean age 66.6 years) were recruited for primary hip replacement with beaded C-Stem femoral components. Tantalum marker beads were injected into the proximal femur, and stems were inserted using CMW1 cement and the latest generation cementing technique via: a posterior approach (17), and a lateral, trochanteric approach (3). RSA X-ray examinations were performed at 1 week, 6 weeks, and at 3, 6, 12, 24 and 36 months postoperatively. The UmRSA system was used to measure and analyse the radiographs.

Results: By 36M the mean stem subsidence (1.05 mm) had levelled off to a low rate, and the mean internal rotation (2.5°) had not significantly changed during the final year (p = 0.08). The mean posterior migration of the stem centroid was 0.54 mm and posterior migration of the femoral head was 1.66 mm (0.25 mm/y during final year).

Discussion: At 36M the mean subsidence rate was very low, and the mean posterior migration was about one third of that reported by Sundberg et al. (BHS Meeting, 2007). Although the mean internal rotation was greater than that reported for the Exeter stem, it had stabilised during the final year. These low rates of migration at 3 years are consistent with the good results found in clinical studies of this femoral component.

In situ fixation of mild slips of the slipped capital femoral epiphysis (SCFE) is a safe and reliable method of treatment. Hardware failure and fractures are reported at the time of pin retrieval. Difficulty in removing these pins is well reported. Major problems can be expected when arthroplasty is necessary years later, if the pins are still inside the proximal femur. Hence we have come up with a novel technique to remove these pins during Primary Total hip arthroplasty.

The hip is exposed through posterior approach, dislocated and the neck is then cut at the usual site. It is then segmented in both sagittal and coronal planes into approximately eight to ten pieces and removed piecemeal. The pins are thus exposed, cleared of any bony debris and hammered retrograde.

By using our simple and novel technique to remove these pins we feel it avoids unnecessary trauma to the outer cortex of femur and also reduces the operating time significantly.

Introduction: The Birmingham Hip Resurfacing(BHR) has shown encouraging early to medium term results. It has tended to be used in patients wishing to achieve high functional activity. However there is little data available to support this notion. The purpose of the study was to report the functional levels of patients following BHR.

Methods: Since February 2000, 313 patients have undergone resurfacing by the senior author. Two hundred and sixty four patients with a minimum 12 month follow-up were assessed for functional activity using the modified UCLA activity score. Patients were asked to score their activity level during the pre-symptomatic period as well as pre-operatively and during follow-up.

Results: The mean age at surgery was 55.7 years. The mean follow-up period was 46.72 months. The revision rate for any reason was 3.8%. The mean pre-symptomatic, pre-operative, one year post-operative and final follow-up UCLA scores were 7.9, 3.7, 6.6 and 7.0 respectively. At one year 89% (235 patients) had improved by at least one activity grade from pre-operative levels and 35% (93 Patients) achieved functional scores the same as, or better than their pre-symptomatic levels. This increased to 45% at final follow-up. Of the 242 patients previously involved in moderate activity(UCLA> =5), 31% regained this activity level at one year, rising to 40% at last follow-up. Only 19% of the 180 patients participating in very active/impact sports(UCLA> =8) obtained these levels at one year, rising to 30% at last follow-up.

Conclusion: This is the first assessment of function after BHR comparing pre-symptomatic scores with those obtained during follow-up. Functional scores continue to improve beyond one year in all groups. Significant numbers of patients can achieve functional levels at least as good as before they developed symptoms from their hip, however, the proportion of patients achieving this goal reduces with increasing pre-symptomatic activity.

Introduction: Hip Resurfacing has increased in popularity, particularly in young, active patients. However, concerns remain regarding metal ion levels, hypersensitivity leading to aseptic lymphocytic-vasculitis-associated lesions(ALVAL) and AVN. The purpose of this study was to document our experience of revising resurfacing arthroplasty for ALVAL.

Methods: All patients undergoing conversion of hip resurfacing to total hip replacement at our institution were reviewed. The notes were reviewed for the reason for revision, the make of the implant, time interval between primary procedure and revision and final diagnosis. Radiographs were reviewed to assess for implant alignment, signs of loosening, neck thinning and AVN.

Results: Out of the 34 patients who had revision surgery 13 were revised for suspected ALVAL, with mean age of 58.8 years at a mean 42.9 months following primary surgery. Of the 13 resurfacings revisions 11 were Birmingham resurfacing and 1 each of Cormet and ASR resurfacing. Groin pain was the presenting complaint in all patients, 5 patients developed their symptoms immediately postoperatively whilst 8 developed symptoms at mean 28.25 months. Haematological investigations were non-diagnostic. Radiographs were normal in 4 patients, whilst 4 demonstrated a loose cup. Thinning of femoral neck and vertical cup alignment were present in 2 patients each while 1 patient had both vertical cup and thinning of femoral neck. All revisions were achieved with primary implants and all patients had immediate pain relief after surgery. Implants and tissue were sent for laboratory analysis. 3 patients had a confirmed histological diagnosis of ALVAL, the remaining cases had identical operative findings and are presumed ALVAL.

Discussion: ALVAL accounts for nearly 1/3 of all our revisions for failed resurfacing arthroplasty. Unexplained pain in patients with resurfacing arthroplasty should be considered for a diagnosis of ALVAL and investigated appropriately. Symptoms tend to resolve reliably following conversion to total hip arthroplasty.

Introduction: We previously reported our results of 98 Charnley Low-Friction Arthroplasty in 76 patients with Paget’s disease of the hip at an average follow-up of 10.4 years. The current report presents the outcome of this procedure at 15 to 30 years.

Methods: A total of 98 Charnley low-friction arthroplasties were performed on 76 patients, 27 men (37 hips) and 49 women (61 hips) with an average age of 67.4 years (range 51–79 years). All operations were performed by the trans-trochanteric or antero-lateral approach.

Results: When component revision was used as the endpoint, the survivorship of the acetabular component was 93% at 15 years (CI, 81% to 98%), 83% at 20 years (CI, 59% to 93%), 72% at 25 years (CI, 41% to 89%) and 36% at 30 years (CI, 2% to 78%). The survival of the femoral component was 91% at 15 years (CI, 80% to 96%), 84% at 20 years (CI, 60% to 94%), 84% at 25 years (CI, 60% to 94%) and 72% at 30 years (CI, 38% to 89%). The survival of both components was 89% at 15 years (CI, 76% to 95%), 81% at 20 years (CI, 56% to 92%), 81% at 25 years (CI, 56% to 92%) and 81% at 30 years (CI, 56% to 92%).

When component failure was used as the endpoint, the survivorship of the acetabular component was 78% at 15 years (CI, 64% to 87%), 66% at 20 years (CI, 48% to 80%), 43% at 25 years (CI, 21% to 62%) and 12% at 30 years (CI, 2% to 32%). The survival of the femoral component was 76% at 15 years (CI, 62% to 85%), 67% at 20 years (CI, 48% to 80%), 47% at 25 years (CI, 25% to 67%) and 7% at 30 years (CI, 1% to 26%). The survival of both components was 74% at 15 years (CI, 59% to 83%), 64% at 20 years (CI, 44% to 78%), 43% at 25 years (CI, 20% to 64%) and 7% at 30 years (CI, 1% to 27%).

Discussion and Conclusion: Long term results using Charnley’s Low Friction Arthroplasty achieved in this patient group are comparable to general arthroplasty population.

(Previous report: Charnley low-friction arthroplasty for Paget’s disease of the hip.

J Arthroplasty. 2000 Feb;15(2):210–9).

Aim: PFC Sigma total knee was introduced in 1997 incorporating a number of design changes. We report our medium-term results of a consecutive series of PFC sigma knees performed between Nov 1997 and Dec 1998.

Method: Between November 1997 and December 1998 a consecutive series of 166 TKAs (156 patients)were carried out using the PFC Sigma total knee replacement system at Wrightington Hospital. Out of the 156 patients 9 were lost to follow-up. This left 147 patients (156 knees) with a mean follow-up of 90 months (range 84 – 96 months). 137 patients (88%) had primary osteoarthritis, 14(9%) had R.A and 5(3%) had post-traumatic arthritis. The mean age was 70 yrs (53 – 88 yrs).85 were female and 62 male. All patients were followed at 3 months, 6 months,1 year and then yearly. Clinical evaluation was done by American Knee Society and Oxford knee scores. Knee society score was used to assess the postoperative radiographs.

Results: The mean Knee society score improved from the preoperative mean of 45 (range 30 – 65) to postoperative mean of 84 points(range 45 – 92). The mean preoperative functional score was 38(range 25 –5) and mean postoperative functional score was 73 points(range 50–95). According to the final scoring 90 % of the knees were rated excellent, 4% good, 4 % fair and 2 % poor. The mean preoperative Oxford knee score was 43 (range 33–52) and mean postoperative score was 17 (14–29). Range of motion improved from a mean of 90(range 50–125) to 105(range 65–130). There was no significant difference (p = 0.03) in the American Knee Society score and Oxford knee score when comparing patients with and without resurfacing of the patella and PCL-retaining with PCL-substituting implants.1 knee (0.6%) was revised within 18 months due to aseptic loosening.1 knee(0.6%) had superficial wound infection which cleared with oral antibiotics.2 patients(2 knees) developed deep infection out of which one resolved following early debridement, the other developed chronic infection requiring long term suppressive antibiotics. 3 patients had proven below knee deep venous thrombosis; one of them developed a non-fatal pulmonary embolism. Radiological review using radiological knee society scoring showed radiolucent lines under 35 % of the tibial components(56 knees)and 11 % of Femoral components(18 knees). For survivorship analysis, the actuarial life- table method was used with calculation of the numbers at risk and the survival rates at annual intervals. The 95% confidence limits were calculated by the method of Rothman. The survivorship at the end of eight year follow-up was 99.40. None of the patellar components failed.

Conclusion: Our study shows excellent clinical results of PFC Sigma Total knee replacement after almost eight years follow-up. We plan to continue monitoring this cohort of patients for long-term results.

Introduction: We performed a retrospective case control study in 80 patients who under went revision hip surgery at our unit.

Methodology: Group A (40 patients), received tranexamic acid and intra-operative cell salvage. Group B (40 patients) a matched control did not receive these treatments. Each group was divided into 4 sub groups; revision of both components, revision of components + bone grafting, revision acetabular component +/− bone grafting and revision femoral component +/− bone graft.

Results: In group A the total number of units transfused was 139 compared to 52 in group B. This represents a reduction in blood usage of 37%. The mean amount of blood transfused from cell salvage in each group was 858mls, 477mls, 228mls and 464mls. There was a significant difference in the amount of blood returned between the groups (p< 0.0001). In the control group 37 patients needed transfusion, in the study group 22 (p< 0.0001). At our unit a cost analysis calculation has shown total revenue saving of £88,000 and a potential saving throughout the trust of £316,688 per year.

Discussion: To our knowledge this is the first study to examine the use of cell salvage and tranexamic acid in revision hip surgery. Our results show that a significant reduction in blood transfusion can be made using this technique. It is vital that blood conserving strategies are developed so that future revision surgery can continue.

Total hip replacement is a successful and reliable procedure for the relief of pain, but the results achieved have been reported to be less successful in younger patients who tend to be relatively more active and place greater demands on prostheses than older patients.

Between 1966 and 1978, 226 Charnley low friction arthroplasties (LFAs) were implanted in young patients with an average age at operation of 31.7 years. Initial results were presented at an average of 19.7 years. We have performed a further retrospective analysis of this cohort at 10 years on from the time of data collection of the original study. Of the original cohort, 112 patients are alive and either under follow-up at our hospital or have been traced to other hospitals. 16 have been lost to follow-up. Mean follow-up was 26.4 years. At the time of final follow-up or death, rate of aseptic loosening of the stem was approximately 80%. Acetabular components proved to be less successful with less than 60% remaining well fixed. Differences in survival were apparent between subgroups with differing original pathology with stem survival greater in those with DDH as opposed to rheumatoid or degenerative arthritis and the opposite being true for socket survival.

This study adds to the available knowledge of the longevity of cemented total hip replacement as performed with unsophisticated cementation techniques and how it may perform in differing patients groups.

Introduction: Some reports have suggested an unacceptable failure rate of Elite Plus stem in the medium term. We have previously argued that other measurements must be made in addition to RSA in order to assess reasons for abnormal migrations. This 3-year RSA study of Elite Plus stems assessed the migration pattern and factors that influenced it.

Method: Twenty five patients (23 OA, 2 RA, mean age 60.4 years (37–81)) underwent Elite Plus THR (single surgeon). A-P radiographs were assessed for cementing technique, and measurements (canal widths, stem orientation, cement thickness etc) were taken using CAD software. Activity score and BMI were also recorded. Multiple factors were assessed for correlation with the main components of migration.

Results: One patient’s stem centroid migrated proximally (due to valgus rotation about the shoulder) and the mean subsidence of the others was 0.297 mm at 36 months. Mean internal rotation and posterior head migration (25 patients) at that time were: 1.42° (CI: 0.99° to 1.86°) and 0.801 mm (CI: 0.526 mm to 1.076 mm), neither being significantly different from migrations at 24 months. One patient’s stem migrated continuously. By 36 months, it had subsided 1.279 mm and internally rotated 4.2°. Some significant correlations (p < 0.05, rho > 0.6) were 3M and 36M subsidence with proximal-medial cement thickness; effective offset with 36M medial migration.

Discussion: The one patient with continuous high migration had the highest activity level. This was corroborated by a wear measurement of 3.5 mm in the contralateral (Charnley) hip which had been in place for 9 years (assuming the head was not scratched). If RSA, 3 years postoperatively, can predict future outcome, the 4% failure rate is similar to the ten year results of the Charnley hip.

A secure bone cement interface between the acetabulum and the cement mantle of the hip socket is an important requirement for the long-term success of a cemented hip arthroplasty. Cement pressurisation after bone bed cleaning enables cement to penetrate interstices of cancellous bone forming a superior fixation strength.

We designed an in-vitro experiment to evaluate the performance of the Exeter, Depuy T-handle and a plunger-type pressurisers using two parameters: cement penetration and cement pressurisation.

The deformation of the flexible pressure head of the DePuy model produced a cement mantle, which is thick at the pole but tapered at its rim and variable in the amount of penetration produced (range 2–8mm) for an estimated similar force. Pressures of up to 60KPa were generated throughout the model acetabulum. The Exeter pressuriser was found to produce cement mantles more compatible with a socket. However, the test results show a wide variation in cement penetration occurring for what was estimated to be a similar applied force (3mm to 9mm at the pole and 5mm to 9mm at the rim). It was also shown to have the disadvantage of causing widely dissimilar pressures at the pole and the rim. The plunger protrusion required to produce 5mm cement penetration was found to be 7.5mm. Since this protrusion can be monitored and controlled by the operator, a cement intrusion of 5mm +/−1mm was found to be reproducible with the plunger-type device. The maximum variation in intrusion between rim and pole was 1 mm. Maximin pressures of 70KPa were generated.

We have presented experimental evidence that suggests that a plunger type of acetabular cement pressuriser may provide a more consistently reproducible level of pressurisation leading to optimal cement penetration.

3610 primary and revision total knee replacements were performed at our hospital between 1969 and 1995. We conducted a survivorship analysis of 3234 primary total knee replacements to construct life tables and calculate survival curves. Each knee replacement was entered once only. Revision was defined as the end point. Data was collected both from patient records and by postal questionnaire. Eight types of knee prostheses were evaluated with best-case and worst-case scenarios compared over a 5, 10 and 15 year period.

The evidence suggests that certain types of prosthesis are more liable than others to fail or to fail early. The “Condylar type devices” which include the Total Condylar, Press Fit Condylar (PFC), Kinematic, Kinemax and Anatomic Modular Knee (AMK) have very similar survivorship curves and in the main have performed well up to a 10 year period. The LCS mobile bearing knee performed extremely well at 5 years. The Attenborough knee had an inferior result while the Load Angle Inlay (LAI) which was a very early resurfacing arthroplasty had the poorest results in terms of survivorship.

Restoration of the mechanical axis is thought to be a critical factor in determining the Outcome of knee replacement surgery. There is strong theoretical evidence that reproduction of this axis improves mechanical loading and hence longevity of the implant. Clinical studies are small in number.

Per-operative use of intra-and-extra-medullary alignment jigs help to determine the distal femoral and proximal tibial cuts. Studies have shown large margins of error using the standard jigs provided with most total knee replacement systems. On this basis computer assisted guidance systems are being introduced such as Orthopilot and BrainLab. These systems allow more accurate placement of the bony cuts and hence improve overall lower limb alignment.

No study has shown conclusively that accurately reproducing the mechanical axis of the lower limb improves survivorship of the implant. Prior to investing in these systems we felt it would be prudent to investigate how critical reproduction of the mechanical axis was in the primary total knee replacement.

We assessed 100 primary kinematic total knee replacements performed in 1990. All case notes were reviewed looking for basic demographics, pathology and clinical outcome.

All cases had a long leg film weight-bearing alignment film taken post-operatively. These were digitised and then analysed using Design CAD 97 software and from this the mechanical axis calculated.

Using these data the patients were divided into two groups. The first were within 3 degrees varus/valgus of the mechanical axis. The second were outside this range. These two groups were then correlated to clinical outcome.

Conclusions: Our results suggest that accurate reproduction of the lower limb alignment and the mechanical axis improves clinical outcome and survivorship of the implant using revision as an endpoint. Our data would support the introduction and use of intra operative computer aided guidance systems.

Fifty-seven revision total knee arthroplasties were performed in our hospital using the TC3 system between 1995 and 1997. Twelve patients died. Forty-five patients were followed up for an average of 5.6 years (range 4 – 7 years). No patients were lost to follow-up.

All patients were clinically and radiologically evaluated. A postal patient satisfaction questionnaire was completed. Two patients were revised; one for infection and one for instability. Survivorship using revision as the end point was 93.3% at 7 years.

Indications for revision were infection (4;9%), instability (38;84%), pain and stiffness (3;7%). 32 (71%) patients were satisfied with their outcome, 7 (16%) were noncommittal and 6 (13%) were disappointed at 5 years. We have analysed the 13 dissatisfied patients and highlight the lessons learned.

Pain and stiffness are not good indications for revision; insert thickness of more than 17.5mm is suggestive of elevation of the joint-line; instead the femoral component should be distalised; step wedges should be used in preference to angular wedges; Always long stem the tibial implant if augments are used; stems should be canal filling with adequate grip on the diaphysis.

We suggest the above lessons we have learned from our initial revision arthroplasty learning curve may correlate to the clinical outcome of this small group of dissatisfied patients.

Aim We have prospectively investigated the effect of tranexamic acid in reducing blood loss and transfusion requirements in primary and revision total hip arthroplasty in a comparative study.

Patients and Methods In the study group, tranexamic acid was given half an hour before the skin incision. (10 mg/kg as an intravenous bolus, followed by 10 mg/kg as intravenous infusion over 6 hours). We recorded the haemoglobin level preoperatively and prior to discharge, and number of units of blood transfused. The total peri-operative blood loss and the fall in haemoglobin after surgery was calculated in consultation with our haematologist. There were 9 primary and 17 revision hip replacements in the study group. We compared the results with a control group of 10 primary and 20 revisions performed during a similar period, without tranexamic acid, recording identical parameters. Thrombo-embolic and wound complications were recorded.

Results Patients receiving tranexamic acid had a mean fall in haemoglobin level of 3.1 g/dl and mean blood loss of 4.1 litres. The control group operated without tranexamic acid had a mean fall in the level of haemoglobin of 3.7 g/dl, and the mean blood loss 5.4 litres. The average number of units of blood transfusion required was 0.77 per patient in the study group compared to 2.03 per patient in the control group. The differences were significant (p value of 0.05). There was no increase in the incidence of complications such as deep vein thrombosis, pulmonary embolism, or wound problems in the study group.

Conclusion Tranexamic acid given prior to surgery reduces blood loss and need for blood transfusion, not only in primary but also in revision hip arthroplasty, without any increase in the rate of thrombo-embolic complications.

Aim: To review the results and complications of revision of the socket in total hip arthroplasty using rim mesh and impaction allograft for reconstruction of segmental and complex defects

Patients & Methods: 43 patients who underwent a revision of the socket in 47 total hip replacements were retrospectively reviewed over a 3 ½ year period. All the patients had segmental or complex bone loss around the acetabulum which was reconstructed using Stryker Howmedica rim mesh, impaction bone grafting and a cemented cup through the posterior approach. Final analysis included clinical review at latest follow-up, radiological evaluation to assess graft incorporation and socket migration and any other complications.

Results: All patients were followed up for a mean period of 14.2 months (range: 2 months-33 months). The mean age at surgery was 58.2 yrs. There were 14 males and 29 females. This was a re-revision in 5 patients. The most common indication for revision was aseptic socket loosening with migration in 39 patients. One patient had a two stage revision for infection, one had socket fracture, and two patients had collapse of bulk graft and socket migration. Superior segmental defect of varying sizes were present in all patients, in addition to which there were central deficiencies, anterior and/or posterior column deficiencies and complex defects. 4 patients had post-operative dislocation, 1 had significant limb length discrepancy, 1 had infection and 1 had transient sciatic nerve palsy. At the latest follow-up all patients had good graft incorporation and no socket migration.

Conclusion: Rim mesh helps in containing a segmental defect of acetabulum provides good immediate support for impacted graft and socket and has produced good early results. However, long term follow-up is necessary to determine the outcome of this construct.

Aim: To undertake clinical and radiological assessment of the TCIII prosthesis for Revision total knee arthroplasty with survivorship analysis.

Methods: We reviewed the clinical and radiological outcome of 57 Total Condylar III (TCIII) prostheses used for revision knee arthroplasty performed between December1995 and December1997 at Wrightington hospital. Twelve patients (12 knees) had died. At a mean follow-up of 6.75 years (range, 5–8years) 45 knees in 43 patients were available for review. None were lost to follow-up. There were 23 women and 20 men, with a mean age of 73 years. Radiographs were analysed for component position, alignment and bone-cement radio-lucencies.

Results: The reason for revision was instability in 38 knees, infection in 4 knees, pain in 2 knees and stiffness in one knee. The mean preoperative Hospital for Special Surgery HSS score was 36, improving to 70 after revision at latest review(p=< 0.001). The mean postoperative range of movement was 95 degrees. 2 prostheses were revised, one for infection and another for instability, Survival analysis using the Kaplan Meier method provided a cumulative survival rate of 95.56 % at 8 years.

Conclusion: The clinical and radiological results of our study support the continued use of the TCIII prostheses in revision total knee arthroplasty with satisfactory outcome in the medium term.

Aim: To undertake clinical and radiological assessment of the TCIII prosthesis for Revision total knee arthroplasty with minimum 5 year follow-up.

Methods: We reviewed 57 Total Condylar III (TCIII) prostheses used for revision knee arthroplasty performed between December1995 and December1997 at Wrightington hospital. Twelve patients (12 knees) had died. At a mean follow-up of 6.75 years (range, 5–8years) 45 knees in 43 patients were available for review. None were lost to follow-up. There were 23 women and 20 men, with a mean age of 73 years. Radiographs were analyzed for component position, alignment and bone-cement radiolucencies.

Results: The reason for revision was instability in 38 knees, infection in 4 knees, pain in 2 knees and stiffness in one knee. The mean preoperative Hospital for Special Surgery HSS score was 36, improving to 70 after revision at latest review (p=< 0.001). The mean postoperative range of movement was 95 degrees. 2 prostheses were revised; one for infection and another for instability. Survival analysis using the Kaplan Meier method provided a cumulative survival rate of 95.56 % at 8 years.

Conclusion: Our study supports the continued use of the TCIII prostheses in revision total knee arthroplasty, wherein the ligaments can be balanced, with satisfactory outcome in the medium term.

In 1999 a statement of best practice in primary total hip replacement was approved by the Council of the British Orthopaedic Association (BOA) and by the British Association for Surgery of the Knee (BASK) to provide a basis for regional and national auditable standards: we have compared practice in the North West of England to this document to ascertain adherence to this guide to best practice.

A direct comparison of data held on the North West Hip Arthroplasty Register for 2001/2002 and BASK/BOA guidelines was performed. 86 surgeons from 26 hospitals were included in the study. A mean of 93.3% of operations were performed in the surgeon’s usual theatre. All of these theatres had vertical laminar air flow systems. 42.2% of respondents routinely used exhaust suits. 68.1% of respondents routinely used impermeable disposable gowns. All surgeons use some form of anti-thromboembolic prophylaxis. 66.2% use a combination of both mechanical and chemical means. All surgeons used antibiotic prophylaxis. The most popular choice of antibiotic was a cephalosporin. 93.7% of surgeons routinely use antibiotic-loaded cement. The PFC and Kinemax prostheses were the most commonly used pros-theses. Interestingly, 97.7% of all first choice implants were cemented. Only 2 surgeons used uncemented TKR. 69.8% of surgeons used a posterior cruciate retaining design. A midline longitudinal skin incision is used by 87.2% of surgeons, a medial longitudinal skin incision by 7.0% and a lateral longitudinal skin incision by 5.8% 0f surgeons. A medial parapatellar capsular incision is preferred by 91.9% with the remainder using mid vastus or trivector retaining capsulotomy. Closure of capsulotomies is performed in flexion by 65.1% and in extension by 34.9%. In patients with osteoarthritis 38.4% routinely resurfaced the patella, 34.9% never resurfaced the patella and 26.7% selectively resurfaced. This was in direct contrast to practice for patients with rheumatoid arthritis in whom 66.3% routinely resurfaced the patella, 22.1% never resurfaced the patella and 11.6% selectively resurfaced.

This study has demonstrated considerable variation of practice in hip arthroplasty across the North West region and significant divergence from the BASK/BOA statement of best practice. The introduction of a properly funded national arthroplasty register will surely help to clarify the effect of such diverse practice on patient outcome.

Introduction Plantar fasciitis is a common presenting problem and there are multiple treatments available. There is little scientific data to assist in the selection of the most efficacious or cost-effective treatment. This study compared the efficacy of corticosteroid injection and low-dose ESWT for the treatment of chronic proximal plantar fasciitis.

Methods One hundred and thirty-two cases of plantar fasciitis were enrolled into this prospective study over five years. Eligible patients performed a stretching program for the gastrocsoleus. In addition, patients randomized to group A received an intralesional corticosteroid injection, while group B received low dose ESWT (3 x 1000 pulses, energy flux density 0.08/mm2). Nineteen patients were not randomized and comprised a control group C. Patients were assessed before, and then three and 12 months post treatment using a VAS, and algometer (tenderness threshold, TT). The groups were compared using generalized linear models for repeated measures of VAS and TT scores, with orthogonal contrasts.

Results The three groups were significantly different in their VAS scores post treatment. Over the 12 months, pain levels reduced for all groups, but the trends between them differed significantly. The corticosteroid (CSI) group, had significantly lower levels of pain than the ESWT or controls. At 12 months, the CSI and ESWT had similar levels of pain, both significantly lower than that in the controls. Similar trends were found for TT. Threshold levels increased for all three groups post treatment but the trends between the groups were significantly different. At three months, the CSI group had significantly higher TTs than both the ESWT and control groups. By 12 months, all groups had higher TTs but they were similar. The TT of the CSI group had plateaued by three months. Of the 64 heels that received CSI, there were no infections and no cases of rupture of the plantar fascia. There were eight cases of post-injection pain. All patients found the injection unpleasant. Of the 61 heels treated with ESWT, six reported throbbing pain and erythema. Four reported a severe headache. All patients found the procedure unpleasant.

Conclusions Intralesional corticosteroid injection is more efficacious, and much more cost-effective, than ESWT, in the treatment of plantar fasciitis present for at least six weeks. The injection achieves a significant and lasting reduction in pain and tenderness within three months. Correctly used, this treatment has a low incidence of complications.

Restoration of the mechanical axis is thought to be a critical factor in determining the outcome of knee replacement surgery. There is strong theoretical evidence that reproduction of this axis improves mechanical loading and hence longevity of the implant. Per operative use alignment jigs help to determine the bony cuts. Studies have shown large margins of error using the standard jigs. On this basis computer navigation systems are being introduced. No study has shown conclusively that accurately reproducing the mechanical axis of the lower limb improves survivorship of the implant. Prior to investing in these systems we felt it would be prudent to investigate how critical reproduction of the mechanical axis was in the primary total knee replacement.

We assessed 100 primary total knee replacements performed in 1990. All case notes were reviewed looking for basic demographics, pathology, and clinical outcome. All cases had a long leg þlm weight bearing alignment þlm taken post operatively. These were digitised and then analysed using CAD software. From this the mechanical axis calculated.

Using this data the patients were divided into two groups. The þrst were within 3 degrees varus/valgus of the mechanical axis. The second were outside this range. These two groups were then correlated to clinical outcome.

Our results suggest that accurate reproduction of the mechanical axis improves clinical outcome and survi-vorship of the implant. Our data would support the use of intra operative computer navigation systems

Aims: Should the tibial tray be rotated about the femoral component of a total knee arthroplasty? Literature review provides evidence commending rotation and neutral alignment. We wanted to provide evidence to help this debate.

Method: We developed a knee jig allowing full range of movement of a knee arthoplasty. Under compression, we studied the isolated effect of tibial tray rotation about the femoral prosthesis in þxed and mobile bearing prostheses. We photographed the tibio-femoral and patello-femoral articulations.

Results: A mobile bearing prosthesis at 15 degrees of tray rotation suffered posteromedial and anterolateral polyethylene impingement. At 25 degrees, the medial femoral component lifted off. The þxed bearing prosthesis showed similar polyethylene impingement, but no femoral condyle lift off. In both prostheses, tray rotation increased lateral patella facet loading, which increased with knee ßexion.

Conclusion: Mobile bearing prosthesis was less tolerant than þxed bearing prosthesis to tibial tray rotation. Rotation caused polyethylene impingement, which would generate wear debris. Patella tracking was not improved by tibial tray rotation. The mobile bearing prosthesis is less congruent at the tibio-femoral articulation. Therefore there is less Òdriving forceÒ to rotate the polyethylene to align it to the femoral component, when the tray is rotated. We recommend the tibial tray be aligned to the femoral prosthesis in neutral.

The aim of this study was to ascertain if a correlation exists between the indication for revision and the clinical outcome in revision total knee replacement.

Methods: We analysed the data of 81 revision knee arthroplasty patients performed at Wrightington Hospital with an average follow-up of 31 months (1yr – 6yrs). All patients had semi-constrained prosthesis implanted (PS-PFC or TC3, Depuy). The indications for revising the total knee arthroplasty in each patient were noted and the clinical outcome was determined using a patient satisfaction questionnaire.

Results: Of the 81 patients, 18 were enthusiastic with the clinical outcome, 38 were satisfied, eight were non-committal and 17 were disappointed. Indications for revision in our series were aseptic loosening (31 patients), implant failure (21 patients), instability (14 patients), pain (eight patients) and infection (seven patients). Correlation between the indication for revision and the clinical outcome are detailed in the table below.

Sixteen per cent of patients revised for aseptic loosening were non-committal or disappointed with the outcome in comparison with 33.3% revised for implant failure, 21.4% revised for instability, 62.5% revised for pain and 71.4% revised for infection.

Conclusion: The indication for revision does affect the clinical outcome in revision knee arthroplasty. Patients undergoing revision knee arthroplasty for infection and pain are less likely to be satisfied with the clinical outcome of revision surgery.

It is usually assumed that there is a correlation between the number of previous operations and the clinical outcome of revision knee arthroplasty though it has not been studied and published. We reviewed our series of 81 revision knee arthroplasty patients to ascertain if a correlation exists. All patients had a semi-constrained prosthesis implanted.

Methods: We analysed the data of 81 revision knee arthroplasty patients performed at Wrightington Hospital with an average follow-up of 31 months (1yr – 6yrs). The number of previous operations on each knee were noted and the clinical outcome was determined using a patient satisfaction questionnaire.

Results: Of the 81 patients; 18 were enthusiastic with the clinical outcome; 38 were satisfied; eight were non-committal; 17 were disappointed. Seventy four per cent of patients with one previous operation were enthusiastic or satisfied with the revision surgery outcome in comparison to 55.5% and 0% of patients with two and three previous surgery respectively.

Conclusion: The trend from the above figures suggests that as the number of previous operations increases the likelihood of satisfactory clinical outcome decreases, in revision total knee replacement using semi-constrained prosthesis.

The clinical results of cemented hip arthroplasty in patients with DDH are excellent in terms of pain relief and implant longevity. The survivorship of the femoral stem in young patients less than 40 years of age is 97% at ten years and falls to 89% at 25 years. In comparison, survivorship of the acetabular component is 97% at ten years but falls to 58% at 25 years. The excellent survivorship of the femoral stem can be explained by a favourable canal flair index, competent cancellous bone, and secure fixation with acrylic cement. The inferior results of the acetabular component are explained by the distorted pelvic anatomy and lack of bone support for the acetabular component. We continue to recommend cemented hip arthroplasty in this cohort of patients. Our current practice is to use fourth generation cementing techniques and to employ autografting of the acetabulum to address some of the anatomical deficiencies of the original anatomy.

Background: Opinions about hinged knee prostheses vary a lot in different studies. We wanted to examine our series to ascertain their continued need in treating severely unstable knee joints and look at the early results.

Methods: 30 rotating hinged knee prostheses were implanted in Wrightington Hospital by the senior author. 4 patients deceased and the remaining knees were retrospectively followed up for an average of 16 months and examined for clinical or radiological factors indicating the overall outcome.

Results: Preoperative diagnosis: Gross instability associated with 12 – aseptic loosening; 18 – infection (15 pseudarthrosis, 1 failed arthrodesis) 19

Preoperatively, 16 patients were wheelchair bound and using a frame as a walking aid and 10 used two crutches for ambulation. 5 patients needed plastic surgical input and 5 needed a whiteside’s osteotomy for exposure. Previous surgery on the knee:

2 patients – 1 surgery

13 patients – 2 surgeries

8 patients – 3 surgeries

5 patients – 4 surgeries

2 patients – more than 4 surgeries

In the latest review, excluding the deceased patients, there were 24 patients (89%) regarded as having satisfactory and 3 patients (11%) unsatisfactory results. 89% of the patients were subjectively satisfied with the operation, mostly because of a stable, mobile knee with minimal pain, in comparison to their pre-operative debilitating condition.

Conclusions: Apart from clinical and radiological examination, preoperative diagnosis, pain, mobility, the number of previous surgeries and need for plastic surgery can be used as factors to assess the preoperative severity/morbidity of the case. Taking into account the very poor initial status of these patients, we recommend the rotating hinged prostheses still to be used in severely unstable knees.

Background: The risks associated with homologous blood transfusion and the increasing shortage of banked blood have brought the need for blood salvage procedures to the forefront.

Post operative blood salvage and autologous blood transfusion have been used though the financial implications of their use has not been assessed in the UK.

Methods: We carried out a retrospective study of 98 consecutive unilateral Total Knee Replacements performed in 96/97, under the care of one consultant, of these 55 had non-autologous drains and 43 had autologous drains after surgery.

Results:

Mean blood loss (non-autologous system) – 778mls

Mean blood loss ( autologous system) – 633mls

Total cost for use of non-autologous drainage system and associated transfusion – 8,346.00

Conclusions: Autologous drains decreased the need for homologous blood transfusion by 69% and brought about a financial saving of 26%. There were no complications arising from the use of autologous drains. There was less blood loss with the use of autologous drains than non-autologous drains in our study.