Introduction

Gaucher Disease (GD) is the commonest of the lysosomal storage disorders. Orthopaedic manifestations occur in 90% and include osteonecrosis of the femoral head, often producing severe disability at a young age. Historically, arthroplasty has been avoided in GD due to high reported rates of haemorrhage and decreased implant survival. The advent of enzyme replacement therapy (ERT) has revolutionised GD treatment with correction of haematological parameters within five months. However there is little data regarding the effect of ERT on the outcomes of hip arthroplasty.

Total hip-joint arthroplasty is associated with a high rate of perioperative blood transfusion, which increases the risk of blood-borne disease, anaphylactic and haemolytic reactions. Devices are used which collect and allow the re-infusion of blood lost during surgery, with the aim of reducing allogenic blood transfusion requirements. The purpose of this study was to establish whether the use of a ‘cell-saver’ device reduces the risk of post-operative allogenic blood transfusion in total hip joint arthroplasty.

All total hip arthroplasties performed by a single surgeon over a twelve month period were divided into two cohorts of patients; one which used an intra-operative cell saver device, the other which did not. Data was collected for patient demographics, pre-operative blood tests and blood loss, with the outcome measure as post-operative transfusion requirements. The total number of patients was 233; 166 primaries, 33 resurfacing & 20 revision arthroplasties: 14 excluded for insufficient data.

Comparison of the two cohorts (intra-operative cell saver used vs. no cell-saver used), demonstrated no significant difference in the post operative blood transfusion requirements for patients undergoing primary total hip joint arthroplasty (n=166, 18.3% vs. 11.0%, p=0.08), Birmingham resurfacing arthroplasty (n=33, 5% vs. 7.7%, p=0.49), and revision arthroplasty (n=20, 28.6% vs. 50%, p=0.26). There were no significant differences demonstrated between the patient demographics of the two cohorts for any of the groups. In the cell-saver cohort, the average volume of blood re-transfused was 117mls per patient (range 0 – 400mls).

Intra-operative use of cell-saver devices does not decrease post-operative transfusion requirements in primary hip arthroplasty. A larger size study is required to assess the outcome in resurfacing and revision hip arthroplasty surgery.

Introduction: Serial reamers of incremental diameter are used in the preparation of the acetabulum in Total Hip Arthroplasty. If the reamer is blunt then the size of the reamed acetabulum may not accurately represent the size of the last reamer used. This inaccuracy may then adversely affect implant selection or implantation.

Methods: Traditional debris-retaining cheese grater ace-tabular reamers were used to create a cavity in a foam block, following a standardised technique. A casting was then made of the cavity, the diameter of the cast measured and compared to that of the reamer. Accuracy was defined as the difference between the observed and expected diameters. Measurements were collected for five different hip systems (78 reamers in total)

Results: Sixty-four out of the seventy-eight reamer tested were inaccurate. There was a significant difference between groups. Only reamers from one of the five systems tested consistently created cavities which accurately matched their stated size. Two systems consistently produced a cavity that was at least 1mm smaller than intended. In the majority of cases the mid-range reamers, sizes (46–52mm) were the most inaccurate.

Discussion: The majority of acetabular reamers in our study were inaccurate. If this is unintentional, it suggests reamers may become increasingly blunt with use and should be calibrated, sharpened or replaced.

There is suggestion our National Joint Replacement Registry (ANJRR) does not recognize ‘the surgical learning curve’ for new prostheses. Prostheses introduced post-Registry have the learning curve revisions captured. Prostheses introduced pre-Registry will not and will be advantaged. This paper presents the evidence for this and makes suggestions to correct this issue. A literature search was made for surgery learning curve references. The Swedish Knee Arthroplasty Register was reviewed for learning curve references. The ANJRR reports were examined for evidence of learning curve revisions inclusion in cumulative revision rate curves using Unicompartmental Arthroplasty data. An Internet search reveals 212 references on ‘surgery learning curve’. Some discuss the particular issue of minimally invasive surgery (MIS). The 2004 Swedish Knee Arthroplasty Register (SKAR) report mentions the trend towards increased revision rates when Unicompartmental Arthroplasty was inserted with MIS. The 2006 SKAR report discussed this issue further suggesting the method may initiate a new learning process which can be shortened if the surgeons are offered training before they start using the method. In 2004 the Australian National Joint Replacement Registry report showed that a new Unicompartmental Arthroplasty (Preservation) had a high early revision rate. This prosthesis was launched in 2002 as a minimally invasive product. That report data was used by several prostheses companies and surgeons to widely highlight the prosthesis “poor performance”. The 2007ANJRR report shows that Preservation now has the lowest 2 to 4 year revision rate of all Unicompartmental prostheses. If the surgery learning curve was excluded the prosthesis would not have been disadvantaged in its early data reports. The evidence is that the learning curve exists and disadvantages new prostheses in ANJRR reporting. This now discourages prosthesis companies from launching new products here. Solutions recommend are:

The ANJRR accept and support the issue of “the learning curve” and the adverse impact this has on post ANJRR prosthesis revision rate data & graphs compared with pre ANJRR prostheses.

Introduction: Total hip-joint arthroplasty is associated with a high rate of peri-operative blood transfusion, which has associated risk. Previous studies have identified individual factors than can predict those patients most at risk of post-operative allogenic blood transfusion. We undertook this study to attempt to identify further factors that may predict post-operative blood transfusion.

Methods: Data was collected pre-operatively for patient demographics including type of surgery, sex, age, BMI, ASA, pre-operative haemoglobin & pre-operative packed cell volume for all total hip arthroplasties performed by a single surgeon over twelve months (Total number 233; 166 primaries, 33 resurfacing & 20 revision arthroplasties: 14 excluded for insufficient data). Post-operative data collection included post-operative haemoglobin levels and allogenic transfusion requirements.

Results: Of 166 patients who underwent primary hip arthroplasty, 25 (15.1%) received allogenic blood transfusions, an average volume of 2.1 units per patient transfused. Analysis revealed significant predictive factors of gender (females > males, p=0.0019), advancing age (p=0.0045), lower height (p< 0.0000), lower pre-operative weight (p=0.0010), lower pre-operative haemoglobin (p< 0.0000), and lower pre-operative packed cell volume (p< 0.0000). Patients who underwent revision surgery were also more likely to have undergone transfusion compared to both primary (6.1% transfused, p=0.025) and resurfacing arthroplasty (35% transfused, p=0.009). BMI and ASA were found to not be significant risk factors. Pre-operative packed cell volume (PCV) showed the strongest correlation with post-operative blood transfusion. Cases with a PCV below the average of 39% had a rate of transfusion of 28%, 6.4 times greater than for those patients above the average at 4.4% (p< 0.0000).

Discussion: Pre-operative measurements of height, weight, haemoglobin and packed cell volume, together with factors including sex & type of surgery can identify those patients who are at greater risk of post-operative transfusion allowing selective transfusion prevention strategies.

Between 29th May 2001 and 15th May 2003, 233 consecutive Preservation unicompartmental knee replacements (UKR) were performed. Of these, 30 were lateral UKRs (13%) performed in 12 men and 16 women (2 bilateral cases) with a mean age of 67 years (range 36 to 93 years). A metal-backed mobile bearing tibial component was used in 13 knees and an all-polyethylene fixed bearing tibial component in 17 knees. The patients were reviewed prospectively at 1 and 2 years. The 2 year results show no difference in range of motion or function between the mobile and fixed bearing versions of the Preservation knee when used on the lateral side. This is similar to the reported results on the medial side. There were 3 early revisions, all in the mobile bearing group. The incidence of revision has been reduced by the introduction of an improved cementing technique.

The aim of this study was to assess the perioperative complications associated with bilateral simultaneous UKR and compare them with those of unilateral UKR and bilateral TKRs. Over a 2 year period, 40 patients underwent bilateral simultaneous Preservation unicompartmental knee replacement UKR. They were compared to 40 matched unilateral UKRs and 28 bilateral simultaneous total knee replacement patients who had their operations during the same time period by the senior author. There was no significant difference between the groups in terms of age, weight, ASA grade and throm-boprophylaxis received. There was no statistically significant difference in the complication rates of all 3 groups. When compared to 2 unilateral UKRs, bilateral simultaneous UKR results in a reduced operative time, blood loss and hospital stay but more blood transfusion. When compared to bilateral TKRs, bilateral simultaneous UKR results in reduced blood loss, reduced blood transfusion and hospital stay but an increased operative time. Bilateral UKR is a useful option in selected patients with bilateral unicompartmental osteoarthritis.

The aim of this prospective cohort study is to compare the early results in a single surgeon series of the mobile and fixed bearing versions of the Preservation UKR for lateral OA. Lateral UKRs were only considered for patients with isolated lateral compartment osteoarthritis with a functioning anterior cruciate ligament. Mild patellofemoral osteoarthritis was not considered a contraindication. If there was any doubt over the condition of the medial compartment or patellofemoral joint, single photon emission computed tomography was performed. Significant uptake it the medial or patellofemoral joint was considered a contraindication. Patients were assessed preoperatively and at 1 and 2 years postoperatively with the American Knee Society Score (AKSS), Oxford Knee Score (OKS) and with anteroposterior, lateral and Rosenberg radiographs.

Between 29^th May 2001 and 15^th May 2003, the senior author (GK) performed 233 consecutive Preservation UKRs. Of these, 30 were lateral UKRs (13%) performed in 12 men and 16 women (2 bilateral cases) with a mean age of 67 years (range 36 to 93 years). A metal-backed mobile bearing tibial component was used in 13 knees and an all-polyethylene fixed bearing tibial component in 17 knees. Patients in the mobile bearing group were significantly younger (t test; p< 0.0001) and had better AKSS knee (Mann-Whitney U test; p=0.05) and AKSS function scores (Mann-Whitney U test; p=0.005). The patients were reviewed after a minimum of 2 years (range 2 to 3.4 years). There was no significant difference between the 2 groups. There had been 3 revisions in the mobile bearing group for tibial loosening and none in the fixed bearing group (chi squared test; not significant). There was 1 tibial periprosthetic fracture in the fixed bearing group. This study shows that the choice of bearing type makes little difference in clinical outcome or range of motion over the first 2 years when using the Preservation Knee. A similar good functional result was obtained with a fixed bearing despite the mobile bearing group being younger and having significantly better preoperative AKS knee and function scores. The 3 revisions for tibial loosening in the mobile bearing group are a concern. However, these results are short-term and there may be improved implant longevity in the long-term with mobile bearing tibial components due to reduced polyethylene wear.

Prior studies have compared the bacterial load observed in laminar flow operating theatres (LFOTs) and standard operating theatres (STOTs) by wound culture and air sampling during surgery. However many organisms responsible for low grade infection after THR are not readily identified on routine culture and may be detectable only by more sensitive techniques such as the poly-merase chain reaction (PCR). This study assessed the wound contamination rate during THRs and compared the results in STOT with that in LFOTs using PCR.

We recruited patients undergoing primary THR for osteoarthritis. Surgery was performed in either STOTs or LFOTs, using identical skin preparation solutions, surgical drapes and operating attire. Specimens of the deep tissue, taken at the beginning and end of surgery, were each immediately separated into two sterile containers, one sent for culture (aerobic, anaerobic and enriched meat broth) and the other frozen at minus 80 degrees Celsius for PCR at a later date.

In each theatre type, 40 specimens from 20 THRs were analysed by both PCR and culture. Using PCR, bacterial DNA was identified on 12 of 40 specimens (30%) from STOTs, of which 3 were taken at the start of surgery and 9 at the end of the surgery, giving a 45% wound contamination rate (9 of 20). Two specimens (5%), both taken at the end of surgery, were positive on enriched culture. In LFOTs, bacterial DNA was identified by PCR on 8 of 40 specimens (20%), of which 2 were taken at the start of surgery and 6 at the end of surgery, giving a 30% wound contamination rate (6 of 20). No specimens were positive on enriched culture.

Wound contamination of primary THR occurs frequently in both STOTs and LFOTs. Although STOTs showed evidence of more frequent wound contamination than LFOTs, with the numbers available, no significant difference was detected. These data remind us the importance of aseptic surgical technique as significant wound contamination can occur despite the use of ultra clean air operating theatres.

Aims: Post-operative check radiographs after primary total hip replacement are routine practice in many orthopaedic units. However they can be uncomfortable for patients and are often of poor quality. We conducted a prospective study to assess the quality of post-operative check radiographs after total hip replacement and to establish whether they alter the management of the patient.

Patients and method: We included 50 consecutive patients that underwent a primary total hip replacement in our study. During the post-operative period A-P and lateral check radiographs of the hip were performed. For each patient, any change in management and the time to discharge were recorded. The quality of each set of radiographs was assessed using a standard proforma (0–10) and scored by two independent observers.

Results: The mean age of the patients was 68 years (range 39 to 83 years). The median time to x-ray was 4.0 days from operation and the median length of stay was 7.0 days. Overall 7 (14%) patients had their discharge delayed by a mean time of 2.0 (±0.89) days waiting for post-operative radiographs. The mean score for quality of radiographs was 8.12 (±1.32) with good inter-observer and intra-observer agreement. In total, 15 (30%) sets of radiographs were of inferior quality (a score of 7 or less). None of the patients had their management altered by the post-operative radiographs.

Conclusion: We conclude that initial post-operative radiographs are of inferior quality and do not alter the management of the patient. Consideration should be given to performing check radiographs at the first out-patient clinic follow-up as an alternative.

Twenty patients underwent simultaneous bilateral medial unicompartmental knee arthroplasty. Pre-operative hip-knee-ankle alignment and valgus stress radiographs were used to plan the desired post-operative alignment of the limb in accordance with established principles for unicompartmental arthroplasty. In each patient the planned alignment was the same for both knees. Overall, the mean planned post-operative alignment was to 2.3° of varus (0° to 5°).

The side and starting order of surgery were randomised, using conventional instrumentation for one knee and computer-assisted surgery for the opposite side.

The mean variation between the pre-operative plan and the achieved correction in the navigated and the non-navigated limb was 0.9° (sd 1.1; 0° to 4°) and 2.8° (sd 1.4; 1° to 7°), respectively. Using the Wilcoxon signed rank test, we found the difference in variation statistically significant (p < 0.001).

Assessment of lower limb alignment in the non-navigated group revealed that 12 (60%) were within ± 2° of the pre-operative plan, compared to 17 (87%) of the navigated cases.

Computer-assisted surgery significantly improves the post-operative alignment of medial unicompartmental knee arthroplasty compared to conventional techniques in patients undergoing bilateral simultaneous arthroplasty. Improved alignment after arthroplasty is associated with better function and increased longevity.

Introduction and Aims: The aim of this study was to report the two-year results of a new tibio-femoral Uni-compartmental Knee Arthroplasty (UKA) designed specifically to be implanted through a minimally invasive approach.

Method: A prospective review of a single surgeon’s experience with the Preservation UKA was undertaken. The initial 54 UKAs from a consecutive cohort of 253 UKAs that had reached two-year follow-up were evaluated, clinically using the AKSS and OKS scores, and also radiographically. The average age of patients was 66.9 (range 48–82), with a slight male preponderance (1.2:1). Forty-five UKAs were for medial compartment OA (40 all polyethylene fixed tibial bearing, five mobile bearing), with eight bilateral procedures, and nine were for lateral compartment OA (seven all polyethylene fixed tibial bearing, two mobile bearing).

Results: There were no losses to follow-up. The pre-operative AKSS knee and function scores improved from 39 and 56 respectively, to 93 (range 46–100) and 92 (range 10–100) respectively, at last review. The OKS had improved from 39 to 19 (range 12–40), and the average range of motion was 135 degrees (range 125–140). There were no failures requiring revision. Only two patients had poor results, one secondary to a post-operative work related injury and the other due to soft tissue impingement that responded to arthroscopic debridement. One patient was excluded due to a femoral neck fracture. One patient experienced a superficial wound infection, and one patient had a pulmonary embolus. Radiographs revealed minor tibial lucencies in three UKAs, none of which were symptomatic, or progressive to date.

Conclusion: This is the first report documenting two-year results of this new prosthesis, and preliminary results suggest it can produce good clinical and functional results.

Introduction: Although there is evidence that laminar flow operating theatres (LFOTs) can reduce the incidence of wound infection over standard operating theatres (STOTs) when no routine peri-operative antibiotics were used, the evidence for the use with concurrent parenteral antibiotics is less compelling. A number of prior studies have compared the bacterial load observed in LFOTs and STOTs by wound culture and air sampling during surgery. However many organisms responsible for low grade infection after THR are not readily identified on routine culture and may be detectable only by more sensitive techniques such as the polymerase chain reaction (PCR), a molecular biology test for the presence of bacterial DNA. The purpose of this study was to compare the wound contamination rate during THRs performed in STOT with that in LFOTs using PCR.

Method: Patients undergoing primary THR for osteoarthritis without a history of joint infection were recruited for the study. Surgery was performed in either STOTs or LFOTs, using identical skin preparation solutions, surgical drapes and operating attire. Specimens of the deep tissue, taken at the beginning and end of surgery, were each immediately separated into two sterile containers, one sent for culture (aerobic, anaerobic and enriched meat broth) and the other frozen at minus 80 degrees Celsius for PCR at a later date.

Results: In each theatre type, 40 specimens from 20 THRs were analysed by both PCR and culture (80 specimens and 40 THRs in total).

Using PCR, bacterial DNA was identified on 12 of 40 specimens (30%) from STOTs. Of these 12, three were taken at the start of surgery and nine at the end of the surgery, equivalent to a 45% wound contamination rate (9 of 20). Only two specimens (5%), both taken at the end of surgery, were positive on enriched culture.

In LFOTs, bacterial DNA was identified by PCR on eight of 40 specimens (20%). Of these eight, two were taken at the start of surgery and six at the end of surgery, equivalent to a 30% wound contamination rate (6 of 20). None of the specimens were positive on enriched culture.

Discussions: We concluded that wound contamination of primary THR occurs frequently in both STOTs and LFOTs. Although STOTs showed evidence of more frequent wound contamination than LFOTs, with the numbers available, no significant difference was detected. These data are important in that they confirm that continued vigilance to technique continue to be important as significant wound contamination can occur despite the use of ultra clean air operating theatres.

Introduction and Aims: The aim of this study was to report the two-year results of a new tibio-femoral Uni-compartmental Knee Arthroplasty (UKA) designed specifically to be implanted through a minimally invasive approach.

Method: A prospective review of a single surgeon’s experience with the Preservation UKA was undertaken. The initial 54 UKAs from a consecutive cohort of 253 UKAs that had reached two-year follow-up were evaluated, clinically using the AKSS and OKS scores, and also radiographically. The average age of patients was 66.9 (range 48–82), with a slight male preponderance (1.2:1). Forty-five UKAs were for medial compartment OA (40 all polyethylene fixed tibial bearing, five mobile bearing), with eight bilateral procedures, and nine were for lateral compartment OA (seven all polyethylene fixed tibial bearing, two mobile bearing).

Results: There were no losses to follow-up. The pre-operative AKSS knee and function scores improved from 39 and 56 respectively, to 93 (range 46–100) and 92 (range 10–100) respectively at last review. The OKS had improved from 39 to 19 (range 12–40), and the average range of motion was 135 degrees (range 125–140). There were no failures requiring revision. Only two patients had poor results, one secondary to a post-operative work-related injury and the other due to soft tissue impingement that responded to arthroscopic debridement. One patient was excluded due to a femoral neck fracture. One patient experienced a superficial wound infection, and one patient had a pulmonary embolus. Radiographs revealed minor tibial lucencies in three UKAs, none of which were symptomatic, or progressive to date.

Conclusion: This is the first report documenting two-year results of this new prosthesis, and preliminary results suggest it can produce good clinical and functional results.

Introduction and aims: The aim of this study was to determine the relationship between pre-operative Single Photon Emission Tomography (SPECT) scan findings and intra-operative assessments of patello-femoral and tibio-femoral OA, in patients undergoing tibio-femoral uni-compartmental knee arthroplasty (UKA).

Method: Over a six-month period 36 knees in 30 patients, undergoing UKA, were investigated pre-operatively with a SPECT scan to confirm single compartment disease. The male to female ratio of patients was 18:12, with an average age of 63 years (range 44–78). A single radiologist reported all cases, and graded uptake in each compartment. At surgery, the degree of OA encountered in each compartment was assessed by size and grade by the two senior authors, and assigned an OA score. The data was analysed statistically for an association between the SPECT scan score and OA score, using Kendall’s Tau-b.

Results: A statistically significant relationship was demonstrated between positive uptake in a compartment and the presence of OA (p < 0.05), and this was consistent for all compartments. When analysed specifically, the associations were strongest in the medial femoral condyle (0.58) and the medial tibial plateau (0.67), and weakest in the patella (0.35) and trochlea (0.46), and lateral tibial plateau (0.34).

Conclusion: We conclude that SPECT scans can provide useful information regarding the degree of OA in knee compartments when planning UKA, particularly with medial compartment disease. The lower degree of association between scan findings and OA encountered in the patello-femoral compartment, and lateral tibial plateau, indicates greater vigilance should be applied when making intra-operative assessments of these areas.

Aim: To clarify the issue of whether or not to cement the hemiarthroplasty in the treatment of displaced intra-capsular femoral neck fractures in the elderly. Method: All patients with displaced intracapsular femoral neck fractures treated with hemiarthroplasty between January 1997 and May 1998, in 2 hospitals within the same Deanery, were reviewed. The same prosthesis was used; in hospital A they were uncemented, and in B cemented. There were 121 patients in hospital A and 123 in hospital B; all patients alive at follow-up (50 and 56 respectively) were interviewed for pre-fracture and current assessments of pain and functional ability using validated scoring systems. Follow-up was 32–36 months. Results: Patient demographics were similar. Cemented procedures took 15 minutes longer. In-patient stay was the same. Signiþcantly fewer of the cemented group had been revised or were awaiting revision (p=0.036). There was no difference in mortality rates at any point. Prospective assessment of surviving patients revealed highly statistically signiþcant greater deterioration in pain (p=0.003), walking ability (p=0.002), use of walking aids (p=0.003) and activities of daily living (p=0.009) in the uncemented group. The trend for more dependent accommodation in the uncemented group failed to reach statistical signiþcance (p=0.14). Conclusions: Our þndings support the use of cemented hemiarthroplasty for displaced intracapsular femoral neck fractures in the elderly.

The purpose of this study was to determine if routine x-ray exposure produced any chemical oxidation of Ultra High Molecular Weight Polyethylene (UHMWPE), used for joint arthroplasty.

Three different polyethylene polymers were obtained from Biomet, Depuys and Howmedica. These samples had undergone sterilisation and packaging methods. Rectangular shapes of polymer were cut according to the standards specified by the ASTM (American Society For Testing and Materials). Eight samples of each polymer were obtained and divided randomly in to test and control subgroups. The test samples were exposed to ten x-rays with the standard dose used for the hip joint.

Polyethylene oxidation was measured using Fourier transform infrared spectroscopy. This technique can assess the incorporation of oxygen within the carbonyl region. Radiated and non-irradiated samples were compared in each polymer group.

Oxidation from the Fourier transform infrared spectroscopy was quantified by calculating the area under a signature absorption peak for UHMWPE (methylene band at 1370 cm-1) and an oxidation absorption peak (carbonyl band at 1720 cm-1). The ratio of the area of the oxidation peak to the area of the signature peak yields the carbonyl content, or oxidation, relative to the amount of polyethylene. There was no significant difference in oxidation after exposure to x-rays between test and control UHMWPE samples.

Although numerous studies have looked in to the effects of high dose radiation exposure on polyethylene, effects of routine x-rays have not been studied before. It is common practice to follow-up patients with joint replacements over a long period with xrays at each visit. Present study examined the effects of routine x-rays on oxidation of polyethylene. However there was no detectable oxidation after exposure to x-rays. This study paves way for further research in this direction.

Introduction: The best method of management of displaced intracapsular femoral neck fractures in elderly patients remains undecided. Most are treated by hemiarthroplasty.

Aim: To clarify the issue of whether or not to use cement in hemiarthroplasty for displaced, intracapsular, femoral neck fractures in the elderly.

Methods: Consecutive patients with displaced, intracapsular, femoral neck fractures treated by hemiarthroplasty between January 1997 and May 1998, in two hospitals within one region were reviewed. The same monoblock prosthesis was used; in Hospital A they were uncemented (121 patients), and in Hospital B they were cemented (123 patients). All surviving patients (50 and 56 respectively) were interviewed for assessments of pre-fracture and current pain, walking ability, use of walking aids and activities of daily living (ADL), using validated scoring systems. The average follow-up was 36 months.

Results: The patients’ demographical data were similar (the mean age was 82 and 84 years respectively). There was no greater incidence of intra-operative fall in diastolic blood pressure or oxygen saturation in the cemented group. Cemented procedures took, on average, 15 minutes longer. Fewer of the cemented group had been revised or were awaiting revision (p=0.036). There was no difference in complication or mortality rates at any time between surgery and follow-up (p=0.86). Prospective assessment revealed highly significant differences in favour of cement, in terms of pain (p=0.003), walking ability (p=0.002), use of walking aids (p=0.004) and ADL (p=0.009).

Conclusion: Our findings support the use of cemented hemiarthroplasty for the displaced intracapsular femoral neck fracture in the elderly patient.

Between December 1998 and December 1999 twenty-one patients with painful knee arthroplasties underwent assessment by radionuclide arthrography. There were eleven female and ten male patients, with an average age of 60 years at the time of the index procedure. The index procedure was a primary total knee arthroplasty, primary medial unicompartmental knee arthroplasty and revision medial UKA in seventeen, three and one patients respectively. Nineteen arthroplasties were uncemented and two were hybrids. All patients had previously been investigated by clinical examination, serological testing, fluoroscopic AP and lateral radiographs, and Tc99 bone scan with equivocal results. The presence of radionuclide about the tibial stem was considered diagnostic of tibial loosening. Nine patients underwent revision knee arthroplasty. The presence of radionuclide about the tibial stem correctly predicted a loose tibial component in four of five cases. Similarly, the absence of radionuclide about the tibial stem correctly predicted a stable tibial component in four of four cases. In the single misdiagnosed case the tibial component did not have a large central stem, had focal osteolysis about several screws, but remained stable. Radionuclide arthrogram is a useful tool in the investigation of painful knee arthroplasty. Radionuclide about the tibial stem is the key predictor of tibial component loosening.

This paper reports the authors’ experience of over 850 unicompartmental knee replacements beginning in 1985 with the MG2 uni and then the LCS uni in 1995, and more recently with the Allegretto, Oxford and PFC minimally invasive uni.

Minimally invasive unicompartmental knee arthroplasty (MIU) offers the knee arthritis patient significant benefits compared with total knee arthroplasty. Some of these are especially important for Asian patients, in particular range of movement and ability to squat.

The ideal indications for the MIU are not yet fully established but are becoming clearer. Contraindications are also clearer.

These issues will be discussed in detail. The results in 100 cases of unicompartmental arthroplasty will be presented and discussed along with the complications in these patients. Special considerations and recommendations for the commencement of MIU will also be discussed.

This recent and popular procedure also presents the knee surgeon with significant challenges. However, there are also disadvantages which will be outlined.

The surgical technique of the MIU will be shown in detail. The paper closes on a brief discussion into recent developments by an 8 member international group of knee surgeons of a new MIU offering a choice of fixed or mobile bearing MIU, with precise instrumentation of both the femoral and tibial sides, and the early result of the first 18 procedures in 15 patients (3 bilateral).