A: - determine the incidence of intraoperative periprosthetic femoral fracture (PFF)

B: - determine the incidence of, and the reoperation rate for postoperative PFF

When using either CC or PTS femoral components.

Retrospective review of a consecutive series of 11,018 THAs over a ten-year period. All PFFs were identified using regional radiograph archiving and electronic care systems.

Of the 11,018 THAs 4,952 were CC and 6,066 were PTS. Between groups, age, sex, and BMI did not differ.

A: - 55 (0.5%) had an intraoperative PFF. 44 CC and 11 PTS (p<0.001). 3 patients in each group had a femoral shaft fracture, remaining fractures were either the calcar (20 CC and 2 group) or the greater trochanter (11 CC and 6 PTS).

B: - 91(0.8%) sustained a postoperative PFF. Of those 15 were managed conservatively, 15 were revised and 61 (80.3%) had an ORIF. The CC group had both a lower overall rate of postoperative PFFs (0.7% (36/4,952) vs 0.9% (55/6,066); p = 0.341), and a lower rate of return to theatre (0.4% (22/4,952) vs 0.9% (54/6,066); p = 0.005). 1.3% of male PTS (36/2,674) had a reoperation compared to 0.3% of male CC (7/2,121) (p<0.001).

With regard to stem fracture there were none in the Corail group and 5 in the Exeter group. Of these 2 were sub trunnion and 3 were basal neck.

A: - There were significantly more intraoperative PFFs with CC 44 (0.8%) than PTS 11 (0.2%). However, the majority of fractures were either of the calcar or greater trochanter with no impact on early recovery or one year Oxford scores.

B: - Male PTS were five times more likely to have a reoperation for postoperative PFF. Females had the same incidence of reoperation with either component type.

There were 5 stem fractures in the Exeter group and none in the Corail.

These results represent robust estimates, which are likely to be more accurate than revision only studies typically generated from registry data.

Aims

The overall aim of this study was to determine the impact of deprivation with regard to quality of life, demographics, joint-specific function, attendances for unscheduled care, opioid and antidepressant use, having surgery elsewhere, and waiting times for surgery on patients awaiting total hip arthroplasty (THA) and total knee arthroplasty (TKA).

The significance of periprosthetic fractures about a total hip arthroplasty (THA) is becoming increasingly important. Recent studies have demonstrated post-operative periprosthetic fracture rates are higher amongst cemented polished taper slip (PTS) stem designs compared to collared cementless (CC) designs.

However, in the National Joint Registry, the rate of intra-operative periprosthetic femoral fractures (IOPFF) with cementless implant systems remains higher (0.87% vs 0.42%. p <0.001) potentially leading to more post-operative complications.

This study identifies the incidence of IOPFF, the fracture subtype and compares functional outcomes and revision rates of CC femoral implants with an IOPFF to CC stems and PTS stems without a fracture.

5376 consecutive CC stem THA, carried out through a posterior approach were reviewed for IOPFF. Each fracture was subdivided into calcar fracture, greater trochanter (GT) fracture or shaft fracture.

1:1:1 matched analysis was carried out to compare Oxford scores at one year. Matching criteria included; sex (exact), age (± 1 year), American Society of Anaesthesiologists (ASA) grade (exact), and date of surgery (± 6 months).

Electronic records were used to review revision rates.

Following review of the CC stems, 44 (0.8%) were identified as having an IOPFF. Of these 30 (0.6%) were calcar fractures, 11 (0.2%) GT fractures and 3 (0.06%) were shaft fractures. There were no shaft penetrations.

Overall, no significant difference in Oxford scores at one year were observed when comparing the CC IOPFF, CC non-IOPFF and PTS groups.

There were no CC stems revised for any reason with either a calcar fracture or trochanteric fracture within the period of 8 years follow-up.

IOPFF do occur more frequently in cementless systems than cemented. The majority are calcar and GT fractures. These fractures, when identified and managed intra-operatively, do not have worse functional outcomes or revision rates compared to matched non-IOPFF cases.

Aims

The aim of this study was to determine both the incidence of, and the reoperation rate for, postoperative periprosthetic femoral fracture (POPFF) after total hip arthroplasty (THA) with either a collared cementless (CC) femoral component or a cemented polished taper-slip (PTS) femoral component.

Aims

The aim of this study was to report health-related quality of life (HRQoL) and joint-specific function in patients waiting for total hip or knee arthroplasty surgery (THA or TKA) in Northern Ireland, compared to published literature and a matched normal population. Secondary aims were to report emergency department (ED) and out-of-hours general practitioner (OOH GP) visits, new prescriptions of strong opioids, and new prescriptions of antidepressants while waiting.

The benefit of using acetabular screws in primary total hip arthroplasty (THA) has been questioned in recent years. The disadvantages of using screws include increased operative time, risk of injury to surrounding neurovascular structures and metal ware breakage. Recent large registry studies have reported that screws do not confer a protective effect against acetabular loosening or the presence of osteolysis. Other studies have even described an increased risk of aseptic acetabular loosening with the selective use of screws. We report findings from a multicentre cohort study.

This large cohort study compared clinical outcomes between primary acetabular components that were inserted with and without screws. Independent variables included the presence (or absence) of screws, the total number of screws used and the cumulative screw length (CSL). Outcome measures included all-cause revision, acetabular component revision and acetabular component loosening. Statistical software (Stata/IC 13.1 for Mac [64-bit Intel]) was used to conduct all statistical analyses. A p-value < 0 .05 taken to be significant.

There were 4,583 THAs performed in total. Screws were used in 15.9% (n=733). At a mean follow-up of 5.2 years, the all-cause revision rate in the screw cohort was 1.5% compared to 0.83% in the no screw cohort (p=0.085). There was no difference in acetabular component revision rates for screws (3/733, 0.41%) versus no screws (12/3,850, 0.31%) (p=0.439). The rate of acetabular loosening noted during the time of revision surgery was significantly higher when screws were used in the index procedure (2/733, 0.2%) compared to the no screw cohort (1/3,850, 0.02%) (p=0.017). There was no difference in outcomes when stratifying by the number of screws used or the cumulative screw length.

Primary acetabular components do not require screws for fixation. All cause revision rates and acetabular component revision rates are comparable for the screw and the no screw cohorts. The rate of acetabular component loosening, as observed during revision surgery, is significantly higher when screws are used in the index total hip replacement.

Aims

Tranexamic acid (TXA) is now commonly used in major surgical operations including orthopaedics. The TRAC-24 randomized control trial (RCT) aimed to assess if an additional 24 hours of TXA postoperatively in primary total hip (THA) and total knee arthroplasty (TKA) reduced blood loss. Contrary to other orthopaedic studies to date, this trial included high-risk patients. This paper presents the results of a cost analysis undertaken alongside this RCT.

Abstract

Abstract

Abstract

Tranexamic Acid (TXA) is now commonly used in major surgical operations including orthopaedics. The TRAC-24 randomised control trial aimed to assess if an additional 24 hours of TXA post – operatively in primary total hip (THA) and total knee arthroplasty (TKA) reduced blood loss. Contrary to other orthopaedic studies to date this trial included high risk patients. This paper presents the results of a cost analysis undertaken alongside this RTC.

TRAC-24 was a prospective randomised controlled trial on patients undergoing TKA and THA. Three groups were included, Group 1 received 1 g intravenous (IV) TXA perioperatively and an additional 24-hour post-operative oral regime, group 2 received only the perioperative dose and group 3 did not receive TXA. Cost analysis was performed out to day 90.

Group 1 was associated with the lowest mean total costs, followed by group 2 and then group 3. The difference between groups 1 and 3 −£797.77 (95% CI −1478.22, −117.32) were statistically significant. Extended oral dosing reduced costs for patients undergoing THA but not TKA. The reduced costs in groups 1 and 2 resulted from reduced length of stay, readmission rates, Accident and Emergency (A&E) attendances and blood transfusions.

This study demonstrated significant cost savings when using TXA in primary THA or TKA. Extended oral dosing reduced costs further in THA but not TKA.

Aims

The aim of this study is to assess the impact of a pilot enhanced recovery after surgery (ERAS) programme on length of stay (LOS) and post-discharge resource usage via service evaluation and cost analysis.

The influence of the surgical process on implant loosening and periprosthetic fractures (PPF) as major complications in uncemented total hip arthroplasty (THA) have rarely been studied due to the difficult quantification. Meanwhile registry analyses have clearly shown a decrease in complications with increasing experience. The goal of this study was to determine the extent of variability in THA stem implantation between highly experienced surgeons with respect to implant-size, -position, press-fit, contact area, primary stability and the effect of using a powered impaction tool.

Primary hip stems were implanted in 16 cadaveric femur pairs by three experienced surgeons using manual and powered impaction. Quantitative CTs were taken before and after each process step and stem tilt, canal-fill-ratio, pressfit and contact area between bone and implant determined. 11 femur pairs were additionally tested for primary stability under cyclic loading conditions.

Higher variations in press-fit and contact area between the surgeons for manual impactions compared to powered were observed. Stem tilt and implant sizing varied between surgeons but not between impaction methods. Larger stems exhibited less micromotion compared to smaller stems.

Larger implants may increase PPF risk, while smaller implants reduce primary stability. The reduced variation for powered impactions indicates that appropriate measures may promote a more standardized process. The observed variations between the experienced surgeons may represent the acceptable range for this specific stem design. Variability in the implantation process warrants further investigations since certain deviations e.g. a stem tilt towards varus, might increase bone stresses and PPF risk.

Aims

In total knee arthroplasty (TKA), blood loss continues internally after surgery is complete. Typically, the total loss over 48 postoperative hours can be around 1,300 ml, with most occurring within the first 24 hours. We hypothesize that the full potential of tranexamic acid (TXA) to decrease TKA blood loss has not yet been harnessed because it is rarely used beyond the intraoperative period, and is usually withheld from ‘high-risk’ patients with a history of thromboembolic, cardiovascular, or cerebrovascular disease, a patient group who would benefit greatly from a reduced blood loss.

Aims

We studied the outcomes of hip and knee arthroplasties in a high-volume arthroplasty centre to determine if patients with morbid obesity (BMI ≥ 40 kg/m²) had unacceptably worse outcomes as compared to those with BMI < 40 kg/m².

Aims

A typical pattern of blood loss associated with total hip arthroplasty (THA) is 200 ml intraoperatively and 1.3 l in the first 48 postoperative hours. Tranexamic acid (TXA) is most commonly given as a single preoperative dose only and is often withheld from patients with a history of thromboembolic disease as they are perceived to be “high-risk” with respect to postoperative venous thromboembolism (VTE). The TRanexamic ACid for 24 hours trial (TRAC-24) aimed to identify if an additional 24-hour postoperative TXA regime could further reduce blood loss beyond a once-only dose at the time of surgery, without excluding these high-risk patients.

Aims

Up to one in five patients undergoing primary total hip (THA) and knee arthroplasty (TKA) require contralateral surgery. This is frequently performed as a staged procedure. This study aimed to determine if outcomes, as determined by the Oxford Hip Score (OHS) and Knee Score (OKS) differed following second-side surgery.

Introduction

The enhanced recovery after surgery (ERAS) concept in arthroplasty surgery has led to a reduction in postoperative length of stay in recent years. Patients with prolonged length of stay (PLOS) add to the burden of a strained NHS. Our aim was to identify the main reasons.

Introduction

Previous research has demonstrated increased early complication rates following total hip arthroplasty in obese patients, as defined by body mass index (BMI). Subcutaneous fat depth has been shown to be an independent risk factor for wound infection in cervical and lumbar spine surgery as well as after abdominal laparotomy. The aim of this study was to investigate whether increased peri-trochanteric fat depth was associated with increased risk of early complication following total hip arthroplasty.

Background

91% of blood loss in Total Hip Replacement (THR) occurs in the period after skin closure and the first 24 post-operative hours. TRAC-24 was established to identify if an additional 24-hour post-operative oral regime of Tranexamic acid (TXA) is superior to a once-only intravenous dose at surgery.

Aims

The aims of this study were to determine the indications and frequency of ordering a CT pulmonary angiography (CTPA) following primary arthroplasty of the hip and knee, and to determine the number of positive scans in these patients, the location of emboli and the outcome for patients undergoing CTPA.

Introduction

Radiological inclination (RI) is determined in part by operative inclination (OI), which is defined as the angle between the cup axis or handle and the sagittal plane. In lateral decubitus the theatre floor becomes a surrogate for the pelvic sagittal plane.

Critically at the time of cup insertion if the pelvic sagittal plane is not parallel to the floor either because the upper hemi pelvis is internally rotated or adducted, RI can be much greater than expected. We have developed a simple Pelvic Orientation Device (POD) to help achieve a horizontal pelvic sagittal plane.

The POD is a 3-sided square with flat footplates that are placed against the patient's posterior superior iliac spines following initial positioning (figure 1). A digital inclinometer is then placed parallel and perpendicular to the patient to give readings of internal rotation and adduction, which can then be corrected.

This study aimed to assess the effect of flexion and external rotation on measurement of femoral offset (FO), greater trochanter to femoral head centre (GT-FHC) distance, and neck shaft angle (NSA). Three-dimensional femoral shapes (n=100) were generated by statistical shape modelling from 47 CT-segmented right femora. Combined rotations in the range of 0–50° external and 0–50° flexion (in 10° increments) were applied to each femur after they were neutralised (defined as neck and proximal shaft axis parallel with detector plane). Each shape was projected to create 2D images representing radiographs of the proximal femora.

As already known, external rotation resulted in a significant error in measuring FO but flexion alone had no impact. Individually, neither flexion nor external rotation had any impact on GT-FHC but, for example, 30° of flexion combined with 50°of external rotation resulted in an 18.6mm change in height. NSA averaged 125° in neutral with external rotation resulting in a moderate increase and flexion on its own a moderate decrease. However, 50° degrees of both produced an almost 30 degree increase in NSA.

In conclusion, although the relationship between external rotation and FO is appreciated, the impact of flexion with external rotation is not. This combination results in apparent reduced FO, a high femoral head centre and an increased NSA. Femoral components with NSAs of 130° or 135° may historically have been based on X-ray misinterpretation. This work demonstrates that 2D to 3D reconstruction of the proximal femur in pre-op planning is a challenge.

Unknown femur orientation during X-ray imaging may cause inaccurate radiographic measurements. The aim of this study was to assess the effect of 3D femur orientation during radiographic imaging on the measurement of greater trochanter to femoral head centre (GT-FHC) distance.

Three-dimensional femoral shapes (n=100) of unknown gender were generated using a statistical shape model based on a training data of 47 CT segmented femora. Rotations in the range of 0° internal to 50° external and 50° of flexion to 0° of extension (at 10 degree increments) were applied to each femur. A ray tracing algorithm was then used to create 2D images representing radiographs of the femora in known 3D orientations. The GT-FHC distance was then measured automatically by identifying the femoral head, shaft axis and tip of greater trochanter.

Uniaxial rotations had little impact on the measurement with mean absolute error of 0.6 mm and 3.1 mm for 50° for pure external rotation and 50° pure flexion, respectively. Combined flexion and external rotation yielded more significant errors with 10° around each axis introducing a mean error of 3.6 mm and 20° showing an average error of 8.8 mm (Figure 1.). In the cohort we studied, when the femur was in neutral orientation, the tip of greater trochanter was never below the femoral head centre.

Greater trochanter to femoral head centre measurement was insensitive to rotations around a single axis (i.e. flexion or external rotation). Modest combined rotations caused the tip of greater trochanter to appear more distal in 2D and led to deviation from the true value. This study suggests that a radiograph with the greater trochanter appearing below femoral head centre may have been acquired with 3D rotation of the femur.

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Aims

Our aim was to examine the clinical and radiographic outcomes in 257 consecutive Oxford unicompartmental knee arthroplasties (OUKAs) (238 patients), five years post-operatively.

Anterior-posterior (AP) x-rays are routinely taken following total hip replacement to assess placement and orientation of implanted components. Pelvic orientation at the time of an AP x-ray can influence projected implant orientation.¹However, the extent of pelvic orientation varies between patients.²Without compensation for patient specific pelvic orientation, misleading measurements for implant orientation may be obtained. These measurements are used as indicators for post-operative dislocation stability and range of motion. Errors in which could result in differences between expectations and the true outcome achieved. The aim of this research was to develop a tool that could be utilised to determine pelvic orientation from an AP x-ray.

An algorithm based on comparing projections of a statistical shape model of the pelvis (n=20) with the target X-ray was developed in MATLAB. For each iteration, the average shape was adjusted, rotated (to account for patient-specific pelvic orientation), projected onto a 2D plane, and the simulated outline determined. With respect to rotation, the pelvis was allowed to rotate about its transverse axis (pelvic flexion/extension) and anterior-posterior axis (pelvic adduction/abduction). Minimum root mean square error between the outline of the pelvis from the X-ray and the projected shape model outline was used to select final values for flexion and adduction. To test the algorithm, virtual X-rays (n=6) of different pelvis in known orientations were created using the algorithm described by Freud et al.³The true pelvic orientation for each case was randomly generated. Angular error was defined as the difference between the true pelvic orientation and that selected by the algorithm.

Initial testing has exhibited similar accuracy in determining true pelvic flexion (x̄_error = 2.74°, σ_error=±2.21°) and true pelvic adduction (x̄_error = 2.38°, σ_error=±1.76°). For both pelvic flexion and adduction the maximum angular error observed was 5.62°. The minimum angular error for pelvic flexion was 0.37°, whilst for pelvic adduction it was 1.08°.

Although the algorithm is still under development, the low mean, maximum, and standard deviations of error from initial testing indicate the approach is promising. Ongoing work will involve the use of additional landmarks for registration and training shapes to improve the shape model. This tool will allow surgeons to more accurately determine true acetabular orientation relative to the pelvis without the use of additional x-ray views or CT scans. In turn, this will help improve diagnoses of post-operative range of motion and dislocation stability.

Introduction

Radiological Inclination (RI) is defined as the angle formed between the acetabular axis and the longitudinal axis when projected onto the coronal plane. Higher RI angles are associated with adverse outcomes.

Introduction

The results of cementless total hip arthroplasty (THA) vary with data from the UK national Joint Registry being less favourable than that from the Australian registry. The senior author started using a fully cementless THA in 2005 and we aimed to gauge the performance of the implants based on their revision data.

Aims

The aim of this study was to present data on 11 459 patients who underwent total hip (THA), total knee (TKA) or unicompartmental knee arthroplasty (UKA) between November 2002 and April 2014 with aspirin as the primary agent for pharmacological thromboprophylaxis.

Background

The current orthopaedic literature demonstrates a clear relationship between acetabular component positioning, polyethylene wear and risk of dislocation following Total Hip Arthroplasty (THA). Problems with edge loading, stripe wear and squeaking are also associated with higher acetabular inclination angles, particularly in hard-on-hard bearing implants.

The important parameters of acetabular component positioning are depth, height, version and inclination. Acetabular component depth, height and version can be controlled with intra-operative reference to the transverse acetabular ligament.

Control of acetabular component inclination, particularly in the lateral decubitus position, is more difficult and remains a challenge for the Orthopaedic Surgeon. Lewinnek et al described a ‘safe zone’ of acetabular component orientation: Radiological acetabular inclination of 40 ± 10° and radiological anteversion of 15 ± 10°.

Accurate implantation of the acetabular component within the ‘safe zone’ of radiological inclination is dependent on operative inclination, operative version and pelvic position.

Traditionally during surgery, the acetabular component has been inserted with an operative inclination of 45°. This assumes that patient positioning is correct and does not take into account the impact of operative anteversion or patient malpositioning.

However, precise patient positioning in order to orientate acetabular components using this method cannot always be relied upon. Hill et al demonstrated a mean 6.9° difference between photographically simulated radiological inclination and the post-operative radiological inclination. The most likely explanation was felt to be adduction of the uppermost hemipelvis in the lateral decubitus position. The study changed the practice of the senior author, with target operative inclination now 35° rather than 40° as before, aiming to achieve a post-operative radiological inclination of 42° ± 5°.

Introduction

Operative inclination (OI) is defined as the angle between the acetabular axis and the sagittal plane. With the patient in the true lateral decubitus position, this corresponds to the angle formed between the handle of the acetabular component inserter and the theatre floor intra-operatively.

Ideal cup positioning remains elusive both in terms of defining and achieving target.

Our aim is to restore original anatomy by using the Transverse Acetabular Ligament (TAL). In the normal hip TAL and labrum come beyond the equator of the femoral head therefore if the definitive cup is positioned such that: It is cradled by the TAL; Is ideally no more than 4mm greater in diameter than the original femoral head; Sits just deep to the plane of TAL and labrum (this means that normally we leave the fat pad intact and do not ream down to the true floor).

That should restore joint center in terms of height and offset. If the face of the cup is then positioned parallel and just deep to the TAL and psoas groove that should restore original version. We still use TAL for version in dysplasia because we believe the TAL and labrum compensate for any underlying bony abnormality. However in dysplasia the TAL and labrum fall short of original femoral head equator and therefore in such cases we ream down to the true floor if necessary and use a cup which is often smaller than the original head.

Inclination represents a greater challenge and TAL should not be used as an aid to inclination. Our research has shown that errors in postoperative x-ray inclination above 50 degrees are generally caused by errors in patient positioning when in lateral decubitus. Consequently great care needs to be taken when positioning the patient.

Historically correction of deformity in primary TKA has involved release of collateral ligaments to correct deformity. This has been common to both measured resection and gap balancing techniques but particularly the former. Essentially the collateral ligaments have been released to balance the bone cuts. Another philosophy is to consider that the collateral ligaments do not contract and should never be released. After sacrificing both cruciates I use a tibia first technique. The AP femoral cuts are done by using collateral ligament tension to set femoral rotation and create a rectangular flexion gap which is then measured

A five degree conservative or precut is then made on the distal femur. Critically all osteophytes have now been removed. The extension gap is assessed using a spacer block. In a varus knee the definitive cut is frequently made in more varus to create a balanced extension gap to equal the flexion gap. It is rare to have to release the posteromedial capsule.

In contrast in severe fixed valgus the posterolateral capsule frequently has be cut before the definitive distal femora cut is made. The latter is often in more valgus. I never resurface the patella but ensure good patellar tracking after inserting a cementless mobile bearing knee which is used irrespective of deformity. I am more concerned about gap balance than the mechanical axis.

Essentially the concept proposed is to cut the bone to balance the soft tissues as opposed to the reverse. The aim is to restore pre-morbid alignment and not necessarily a neutral mechanical axis.

Salvage Total Hip Arthroplasty (THA) presents a viable solution following failed treatment of a hip fracture. Several studies have suggested higher complication rate including high dislocation rate associated with salvage THA. The present study evaluates the results and complications of hip arthroplasty performed as a salvage procedure after the failed treatment of a hip fracture and comparison made to Primary THA in osteoarthritis (OA). Between 1992 and 2007, 53 patients with a mean age of seventy years were treated with THA after the failed treatment of a hip fracture under the care of a single surgeon. The indication for conversion arthroplasty was Avascular necrosis head – 24(45.3%), screw cut out – 6 (11.3%), non-union – 2(3.8%), Displaced fracture – 2(3.8%), Secondary OA – 19 (35.8%). The implants retrieved were Cannulated screws – 3, Sliding plate and screw – 46, Spline plate – 2, Smith Petersons nail – 1, Martin Plate – 1. This group of patients were matched for age, sex, side, and ASA grading with a group of 59 patients who underwent THA for primary osteoarthritis (THA-OA group). Posterior approach was used in all cases. Four patients (7.5%) required grafting of cup and 21 patients (39.6%) required soft tissue release. The average blood loss was 555 ml, mean duration of surgery was 85.5 min, average inpatient stay was 6.7 days. Cemented THA was used in 43 patients and Cementless THA in 10 patients. At one year follow up there were no dislocations, one patient had an undisplaced femoral fracture treated in Spica. Three patients had broken screws; one patient with shortening > 1 inch. There was one revision for deep infection. The mean Harris Hip Score (HHS) improved from 28.4 to 82.5 at one year, while the Oxford Hip score (OHS) improved from 50.9 to 21.9 (Old system). When the scores were compared to the THA-OA group there was no difference in the oxford hip scores and the the mean one year HHS in the THA-OA group was slightly higher than the group with salvage THA, but the difference was not statistically significant. Hip arthroplasty is an effective salvage procedure in patients with prior surgery for hip fracture. Most patients have good pain relief and functional improvement. Despite the operative challenges, remarkably few serious orthopaedic complications were associated with this procedure in the present study.

Increasing knee flexion following total knee arthroplasty (TKA) has become an important outcome measure. Surgical technique is one factor that can influence knee motion. In this study, it was hypothesised that stripping of the posterior knee capsule could improve flexion and range of motion (ROM) following TKA. Patients who were undergoing TKA were prospectively randomised into two groups - one group (62 patients) were allocated stripping of the posterior knee capsule (PCS), the other group (66 patients) no stripping (no-PCS). The primary outcome was change in flexion and ROM compared to pre-operative measurements at three time points; after wound closure, 3months and 1year post-operatively. Secondary outcomes were absolute measurements of flexion, extension, ROM and complications. All operations were performed by a single surgeon using the same implant and technique. All patients received identical post-operative rehabilitation. There was a significant gain in flexion after wound closure in the PCS group (p=0.022), however there was no significant difference at 3months or 1year post-operatively. Absolute values of extension (p=0.008) and flexion (p=0.001) 3months post-operatively were significantly reduced for the PCS group. The absolute value of ROM was significantly higher for the no-PCS group at 3months (p=0.0002) and 1year (p=0.005). There were no significant difference in the rate of complications. Posterior capsular stripping causes a transient increase in flexion that does not persist post-operatively. We do not recommend routine stripping of the posterior knee capsule in patients undergoing TKA.

A prospective study of 276 TKA's performed in patients with valgus knee deformity ≥ 10° using a Modified Surgical Technique.

Introduction

The addition of hydroxyapatite in cementless total knee arthroplasty is believed to reduce the time for implant fixation and rehabilitation, reduce the incidence of RLLs and provide long lasting implant stability, through improved osseointegration. We report the results of a prospective, randomised controlled single blinded study comparing the post operative pain, biological fixation and clinical outcomes with the LCS Complete Porocoat and the hydroxyapatite-coated, LCS Complete Duofix mobile-bearing knee systems.

Orientation of the native acetabular plane as defined by the transverse acetabular ligament (TAL) and the posterior labrum was measured intra-operatively using computer-assisted navigation in 39 hips. In order to assess the influence of alignment on impingement, the range of movement was calculated for that defined by the TAL and the posterior labrum and compared with a standard acetabular component position (abduction 45°/anteversion 15°).

With respect to the registration of the plane defined by the TAL and the posterior labrum, there was moderate interobserver agreement (r = 0.64, p < 0.001) and intra-observer reproducibility (r = 0.73, p < 0.001). The mean acetabular component orientation achieved was abduction of 41° (32° to 51°) and anteversion of 18° (−1° to 36°). With respect to the Lewinnek safe zone (abduction 40° ±10°, anteversion 15° ±10°), 35 of the 39 acetabular components were within this zone. However, there was no improvement in the range of movement (p = 0.94) and no significant difference in impingement (p = 0.085).

Alignment of the acetabular component with the TAL and the posterior labrum might reduce the variability of acetabular component placement in total hip replacement. However, there is only a moderate interobserver agreement and intra-observer reliability in the alignment of the acetabular component using the TAL and the posterior labrum. No reduction in impingement was found when the acetabular component was aligned with the TAL and the posterior labrum, compared with a standard acetabular component position.

In response to the recent publication in April 2007 of NICE guidelines on venous thromboembolism, we report our practice and experience of VTE in adult hip and knee arthroplasty.

It is generally agreed that the 2 major complications of VTE are sudden death as a result of pulmonary embolism and post thrombotic syndrome. NICE guidelines make 2 assumptions:

That chemical and mechanical prophylaxis can reduce these complications

We have studied a large cohort of patients who had Aspirin only as chemical prophylaxis to determine the incidence of clinical thromboembolism before and after discharge and the mortality from PE at 90 days. We performed a prospective analysis of consecutive patients undergoing primary total knee and hip replacement from November 2002 to November 2007. In total 2050 patients had total knee replacement and 2203 patients had total hip replacement. All patients were treated at one specialist centre under the care of one surgeon. Data was complete and accurate for all patients at 90 days post-operatively.

Standard practice was the use of 150mg Aspirin from Day 1 post-operatively for a total of six weeks combined with spinal anaesthesia and early mobilisation.

The overall rate for Fatal Pulmonary embolism 0.07% (3/4253), overall death rate 0.3%(13/4253), for treated non-fatal PE 0.66% (28/4253) and for treated above knee DVT was 0.33%(14/4253).

Our data suggests that fatal pulmonary embolism is not common and does not account for most deaths following total hip and knee arthroplasty. We suggest there is no evidence that chemical/mechanical prophylaxis reduces the risk of sudden death from PE following elective primary joint replacement and with modern surgical practice elective hip and knee replacement should no longer be considered high risk procedures.

Introduction: Range of motion (ROM) is an important measure of the success of knee Arthroplasty. The extent to which pain relief contributes to improvements in knee ROM in total knee Arthroplasty (TKA) patients is unknown. This prospective study assessed the separate effects of pain abolition and surgery on ROM in a group of 141-osteoathritic patient’s undergoing TKA. Pain had a significant inhibitory effect on knee ROM. Improvements in ROM following TKA may be primarily due to pain relief.

Methods: 141 randomly selected patients underwent LCS total knee arthroplasty (De Puy). A single surgeon performed all operations, using an identical surgical technique. Passive flexion and extension were measured when awake, under anaesthesia, and post-operatively under anaesthesia.

Paired t-tests were used to test for significant differences between the measurements. Independent samples t-tests were used to test for significant differences between the changes in flexion, extension and ROM between the time points tested.

Results:

When awake the mean flexion was 116.8°, extension 3.8°, and ROM 113.0°

Knee flexion (p < 0.0001) and range of motion (p < 0.0001) were significantly greater and knee extension (p < 0.0001) was significantly reduced following anaesthesia only. A further significant increase in knee flexion (p < 0.0001) and range of motion (p = 0.00014) was observed post –operatively under anaesthetic. However knee extension did not significantly increase further (p = 0.29). The average improvement in range of motion once anaesthetised was 16.4° (SD = 13.1°) with the majority of this improvement due to an increase of flexion (average increase of 13.4° (SD = 11.9°) rather than an increase in extension (average increase of 3.0° (SD = 4.2°).

The combined effect of surgery and anaesthetic was 20.5° (SD = 12.3°), with the majority of this improvement due to an increase of flexion (average increase of 17° (SD = 8.5°) rather than an increase in extension (average increase of 3.6° (SD = 6.0°).

Discussion: Pain abolition resulted in a mean increase of 16.4° in the range of motion, and both TKA combined with pain abolition further increased significantly the range of motion to a mean of 20.5°. This study suggests that improvements in ROM following total knee arthroplasty are primarily due to reduction in the symptoms of pain and that other factors such as surgical technique and prosthesis design can further increase ROM.

Future studies should record the measurements of passive flexion, extension and range of motion in the anaesthetised patient, as this will allow objective assessment of changes in range of movement.

In response to the recent publication in April 2007 of NICE guidelines on venous thromboembolism, we report our practice and experience of VTE in adult hip and knee arthroplasty. It is generally agreed that the 2 major complications of VTE are sudden death as a result of pulmonary embolism and post thrombotic syndrome. NICE guidelines make 2 assumptions:

That chemical and mechanical prophylaxis can reduce these complications

We have studied a large cohort of patients who had Aspirin only as chemical prophylaxis to determine the incidence of clinical thromboembolism before and after discharge and the mortality from PE at 90 days. We performed a retrospective analysis of consecutive patients undergoing primary total knee and hip replacement from November 2002 to November 2007. In total 2050 patients had total knee replacement and 2203 patients had total hip replacement. All patients were treated at one specialist centre under the care of one surgeon. Data was complete and accurate for all patients at 90 days post-operatively. Standard practice was the use of 150mg Aspirin from Day 1 post-operatively for a total of six weeks combined with spinal anaesthesia and early mobilisation. The overall rate for Fatal Pulmonary embolism 0.07% (3/4253), overall death rate 0.31%(13/4253), for treated non-fatal PE 0.66% (28/4253) and for treated above knee DVT was 0.33%(14/4253). Our data suggests that fatal pulmonary embolism is not common and does not account for most deaths following total hip and knee arthroplasty. We suggest there is no evidence that chemical/mechanical prophylaxis reduces the risk of sudden death from PE following elective primary joint replacement and with modern surgical practice elective hip and knee replacement should no longer be considered high risk procedures.

Aim: To develop a flexion jig that would reliably hold the post-op knee in fixed flexion for a defined time period and determine its influence on peri-operative blood loss, transfusion, pain, and complications (specifically nerve palsy)following TKA.

Methods/Results: A previous study in this department showed immediate postoperative flexion to significantly reduce blood loss following TKR. Following this study, time in flexion was increased to 12 hours in an attempt to further reduce blood loss., some patients then developed a painful lower limb nerve palsy. This palsy was caused by pressure from the jig in the popliteal fossa/calf on nerves. The design of the jig was altered to remove pressure from these areas. Because of this design change, we were unsure whether the new jig would have the same blood saving effect, necessitating a new study.

This prospective randomised controlled trial recruited 420 patients into 3 equal groups: extension, 3 & 6 hrs flexion.

This trial found a significant reduction in blood loss(12%, p=0.006) and length of stay(1/2 day, p=0.006) in the 6 hour flexion group, compared the extension group.

There was no significant difference in pain or complication rates (excluding nerve palsy).

2 patients in the 6 hour group had postoperative nerve palsy, however, this palsy was sensory only and markedly different to that found previously. Although the palsy rate in this study is similar(1.4%) to quoted literature rates (1.3%) for TKA, it is difficult to know if the jig was the cause of palsy as the there was a difference between those caused by the old metal jig (painful) and those in this study (sensory loss only).

Conclusion: The results of this study show post-op flexion for 6 hours to significantly reduce perioperative blood loss. Palsy was reduced to match rates as quoted in the literature.

Following the recent publication in April 2007 of NICE guidelines on venous thromboembolism, we report our practice and experience of VTE in adult hip and knee arthroplasty.

It is generally agreed that the 2 major complications of VTE are sudden death as a result of pulmonary embolism and post thrombotic syndrome. NICE guide-lines make 2 assumptions:

That chemical and mechanical prophylaxis can reduce these complications

Methods and Results: We have studied a large cohort of patients who had Aspirin only as chemical prophylaxis to determine the incidence of clinical thromboembolism before and after discharge and the mortality from PE at 90 days.

We performed a retrospective analysis of consecutive patients undergoing primary total knee and hip replacement from November 2002 to November 2007. In total 2050 patients had total knee replacement and 2203 patients had total hip replacement. All patients were treated at one specialist centre under the care of one surgeon. Data was complete and accurate for all patients at 90 days post-operatively.

Standard practice was the use of 150mg Aspirin from Day 1 post-operatively for a total of six weeks combined with spinal anaesthesia and early mobilisation.

The overall rate for Fatal Pulmonary embolism 0.07% (3/4253), overall death rate 0.31%(13/4253), for treated non-fatal PE 0.66% (28/4253) and for treated above knee DVT was 0.33%(14/4253).

Conclusion: Our data suggests that fatal pulmonary embolism is not common and does not account for most deaths following total hip and knee arthroplasty. We suggest there is no evidence that chemical/mechanical prophylaxis reduces the risk of sudden death from PE following elective primary joint replacement and with modern surgical practice elective hip and knee replacement should no longer be considered high risk procedures.

Purpose: The study objective was to measure ‘posterior condylar offset’ (PCO), and tibial slope (TS) following cruciate-sacrificing total knee arthroplasty (TKA), and determine any influence on one-year flexion values following cruciate-sacrificing Total Knee Arthroplasty.

The term ‘posterior condylar offset’ (PCO) is defined as the distance from a line projected along the posterior cortex of the femur to the maximum convexity of the posterior condyles. Its magnitude has been found to correlate with final flexion following PCL-retaining TKA, if reduced by more than 3mm post-operatively. (1)

Tibial slope is the angle between a line drawn parallel to the articular surface and a line drawn perpendicular to the long axis of the tibia on a lateral radiograph. Increasing the tibial slope in PCL-retaining TKA has been shown to improve maximal flexion of an average 1.7 degrees flexion for every extra degree on the tibial slope. (2)

Method: We reviewed the pre and post-operative radiographs of 69 patients who had undergone cruciate-sacrificing TKA. All cases were performed by a single surgeon using the same operative technique. Preoperative and postoperative true lateral radiographs were used to measure the change in PCO and the TS. Pre-operative and one-year flexion was measured using a goniometer.

Results: There were 26 males and 43 females. Mean age was 68 years (range 38 – 87). 67 of the patients had a primary diagnosis of OA, the remaining 2 patients RA.

The mean pre-operative PCO was 25.9 mm (21 – 35), whilst the mean post-operative PCO was 26.9 mm (21 – 34). The difference in preoperative and postoperative PCO ranged from −6 mm to + 5 mm (average, +1mm).

Three patients 4% had more than 3mm reduction in their PCO following TKA (range −4mm to −6mm). 16% had their post-operative PCO increased by more than 3mm (range 4mm – 5mm). The remaining 80% had their PCO restored to within 3mm either way.

The mean post operative tibial slope was 6.6° with a range of 5–9°, 38% measuring 6°, 21% at 7°, 17% at 8°and 5° and the remaining 7% at 9°.

Of the three patients whose PCO was reduced by more than 3mm, one had the same flexion 1 year postoperatively, one had an increase of 14 degrees, and unfortunately the third died before their 1 year review.

Using regression analysis, the strongest predictor of one-year flexion for this study group was the preoperative flexion value. The change in PCO and angle of the tibial slope had no significant influence on one-year flexion.

Conclusion: It would appear that the LCS technique permits satisfactory restoration of PCO and consistent tibial slope as only 4% of patients in this study had a decrease in PCO of more than 3mm and the range of tibial slope was within 5°. We feel these parameters are important however in this study it did not have significant influence on final flexion.

Introduction: A critical determinant of early dislocation following total hip arthroplasty (THA) is correct positioning of the acetabular component. This challenging aspect of THA has not been lessened by the introduction of more minimally invasive techniques. In this paper we introduce a simple and reproducible technique, which uses the transverse acetabular ligament (TAL) to determine cup orientation. We have used this technique as the sole method of cup orientation in our last 1000 consecutive primary total hips.

Methods: One thousand consecutive patients were studied in order to determine the prevalence of early dislocation (within 3 months) following acetabular component placement determined by reference to the transverse ace-tabular ligament. All patients underwent primary total hip arthroplasty via a posterolateral approach with a posterior repair.

Results: At a minimum follow-up of 9 months (range 9–39 months) 6 of the 1000 hips (0.6%) had dislocated.

Conclusion: Although multiple factors are known to contribute to this rate correct placement of the acetabular component is critical. As our results compare favourably with other published series where a posterior repair has been performed by extrapolation we feel that that the TAL does provide an acceptable method of determining cup orientation. The fact that it is independent of patient position on the table and is easy to locate with a minimally invasive approach makes it an attractive method.

Between April 1992 and July 2005, 310 posterior lip augmentation devices were used for the treatment of recurrent dislocation of the hip in 307 patients who had received primary total hip replacements (THRs) using Charnley/Charnley Elite components with a cemented acetabulum. The mean number of dislocations before stabilisation with the device was five (1 to 16) with a mean time to this intervention from the first dislocation of 3.8 years (0 days to 22.5 years). The mean age of the patients at this reconstruction was 75.4 years (39 to 96).

A retrospective clinical and radiological review was carried out at a mean follow-up of six years and nine months (4.4 months to 13 years and 7 months). Of the 307 patients, 53 had died at the time of the latest review, with a functioning THR and with the posterior lip augmentation device in situ. There were four revisions (1.3%), one for pain, two for deep infection and one for loosening of the acetabular component. Radiolucent lines around the acetabular component increased in only six cases after insertion of the device which was successful in eliminating instability in 302 patients, with only five further dislocations (1.6%) occurring after its insertion.

Ensuring the accuracy of the intra-operative orientation of the acetabular component during a total hip replacement can be difficult. In this paper we introduce a reproducible technique using the transverse acetabular ligament to determine the anteversion of the acetabular component. We have found that this ligament can be identified in virtually every hip undergoing primary surgery. We describe an intra-operative grading system for the appearance of the ligament. This technique has been used in 1000 consecutive cases. During a minimum follow-up of eight months the dislocation rate was 0.6%. This confirms our hypothesis that the transverse acetabular ligament can be used to determine the position of the acetabular component. The method has been used in both conventional and minimally-invasive approaches.

Objective: To determine if a standard course of outpatient physiotherapy improves the range of knee motion following primary total knee arthroplasty.

Design: One hundred and fifty patients undergoing primary total knee arthroplasty were recruited and randomly assigned into two groups. Group 1 received a course of physiotherapy with a standard protocol over a six week period within 4 weeks of hospital discharge. Group 2 received no outpatient physiotherapy. All patients received inpatient physiotherapy for the length of their hospital stay. Range of knee motion was measured using a goniometer by members of the outcome team blinded to the randomisation. Validated knee scores (Oxford knee and Bartlet patellar) were collected. An SF12 health questionnaire was used as a generic outcome measure.

Results: Both groups were equally matched by age and sex. Although patients in Group 1 achieved greater range of knee motion than those in Group 2 this was not statistically significant. No difference was also noted in any of the outcome measures used.

Conclusion: We conclude that in patients undergoing primary total knee arthroplasty, inpatient physiotherapy with good instructions and a well-structured home exercise regime can dispense with the need for outpatient physiotherapy.

Objective: To examine the impact of aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) on preoperative haemoglobin levels and perioperative transfusion rates in patients undergoing total knee arthroplasty (TKA).

Methods: We examined the pre-operative haemoglobin (Hb) and haematocrit (Hct) of a consecutive series of 81 patients, looking at the relationship between the pre-operative use of Aspirin/NSAIDs on preoperative Hb, postoperative Hb deficit and the perioperative transfusion rate. A single surgeon performed all procedures using an LCS TKR (Depuy, Leeds UK). A standardised transfusion protocol was used.

Results: The patients were grouped according to their pre-operative use of aspirin or a NSAID, singly or in combination. The patient groups are as shown in the table below. All groups were comparable for age, BMI and ASA grade.

Results show a significantly higher transfusion rate (p=0.048) in the group of patients who received a combination of aspirin and a NSAID compared to the other groups. The patients on aspirin or a NSAID alone also had an increased transfusion rate but the increase was not statistically significant (p=0.12 and p=0.07 respectively).

Conclusion: The use of both aspirin and an NSAID in combination leads to a lower preoperative Hb and an increased post-operative transfusion requirement following total knee arthroplasty.

Current methods for restoring or preserving limb length following total hip arthroplasty are anatomically inaccurate, as they do not consider acetabular and femoral height independently. In order to address this, we present and evaluate a technique that uses the transverse acetabular ligament to control the vertical height of the acetabular component and a caliper that controls the vertical placement of the femoral component within the femoral canal. Limb lengths were measured in 200 patients who had undergone primary total hip arthroplasty using this technique. Using this method, 94% had a post-operative limb length inequality that was 6 mm or less when compared to the normal side (average +0.38 mm). The maximum measured limb length inequality was ± 8 mm.

Background: The positioning of the acetabular component is of critical importance in total hip arthroplasty. Due to the orientation of the acetabulum and limitations of observation imposed at the operative site mal-positioning is common. We believe that by utilising the transverse acetabular ligament (TAL) and acetabular labrum, we are able to anatomically position our cup. In this study, we evaluate the correlation between placement of the acetabular component by reference to the TAL and the acetabular labrum with the taught safe zones for cup placement.

Method: 7 embalmed hips were studied. Following disarticulation the labrum and TAL were digitised and their plane was calculated. Orientation of cup placement in this plane was calculated from a pre-dissection pelvic CT.

Results: The plane of the labrum/TAL varied between 5–26° of anteversion and 32–59° of inclination. Interob-server differences in acetabular cup placement based on the TAL/labral plane indicate reasonable coherence. Almost all components were inside the documented “safe zone” 0–40° of anteversion and 30–55° of inclination of placement.

Conclusion: The acetabular labrum and TAL form a plane that reflects the documented “safe zones” for acetabular component placement. We feel that this plane allows a surgeon to determine optimal patient specific acetabular component placement, irrespective of patient position.

Isolated patellofemoral osteoarthritis has been reported to occur in approximately 5% of patients with gon-arthrosis of the knee. A number of options are available for the surgical management of these individuals. We reported the short-term outcomes on thirty three patients (33 knees) with isolated patellofemoral osteoarthritis who underwent LCS total knee arthroplasty (TKA) without resurfacing who had been operated on between 1996 – 1999¹.

Barrack et al² in 2001 reported on the incidence of anterior knee pain in two groups of TKA patients, one with patella resurfacing and one without. They reported an increase incidence of anterior knee pain in both groups.

We now report the longer-term outcomes with an average follow-up of 80.2months (range 54–94 months). At latest review, 9 patients experienced night time pain, all describing it as improved from their preoperative level. Twelve patients walked with the use of a walking aid, compared with 21 preoperatively. Disease specific scores at latest review showed improved outcome measures at latest review.

We also report our outcomes in an additional fifty-five patients (59 knees) with isolated patellofemoral osteoarthritis who were treated between 1999–2004 receiving an LCS total knee arthroplasty without patellar resurfacing. Our preliminary findings suggest that this technique continues to be an option in the management of the older patient with isolated patellofemoral osteoarthritis.

Introduction: Potential benefits cited for minimally invasive total hip arthroplasty (THA) include reduced peri-operative blood loss, less post-operative pain, earlier mobilisation and a shortened hospital stay. Sceptics, however, are concerned about the widespread introduction of a new surgical technique in the absence of objective scientific evidence. The ever-increasing pressure on healthcare budgets by an ageing population makes developments in surgical technique that allow earlier mobilisation and reduced length of hospital stay highly desirable. The aim of this study was to investigate whether a minimally invasive technique in THA would result in a reduced length of hospital stay compared to a standard incision of 16cm.

Materials and Methods: 219 patients were randomised to either a minimally invasive (less than or equal to 10cm) or standard (16cm) incision group. Patients were blinded to their incision length. Anaesthetic and post-operative analgesic protocols were standardised. A single surgeon performed all operations using an uncemented cup and a cemented stem. Post-operative physiotherapy was standardised with the physiotherapists also blinded to incision length. Patients were discharged when safely able to transfer and mobilise with a walking aid.

Results: There was no statistically significant difference in mean length of stay following surgery. This was 3.65 days (SD 2.04) for the mini-incision group and 3.68 days (SD 2.45) for the standard incision group (p=0.94). 32% of patients (35/110) in the standard incision group were able to go home on day 2 compared to 27% (29/109) in the mini-incision group. Using logistic regression analysis, the patient variables most significantly associated with a probability of discharge within 3 days of surgery were patient age (Wald=33.36, p< 0.0001) and pre-operative haemoglobin (Wald=10.53, p=0.001).

192 patients (88.5%) were discharged to their own homes with the main determinant of discharge to the patients’ own home being the availability of adequate family support.

Conclusion: Total hip arthroplasty performed through a single incision minimally invasive approach does not reduce the length of hospital stay compared to THA performed through a standard incision of 16cm.

Purpose: The objective of this study was to examine the relationship between aspirin and other non-steroidal anti-inflammatory drugs (NSAIDS) on postoperative blood loss following Total Knee Arthroplasty

Methods: We prospectively examined the pre-operative consumption of aspirin and NSAIDS and haematological parameters of 50 consecutive patients undergoing Total Knee Arthroplasty. 22 (44%) patients were on aspirin only, 17 (34%) patients on aspirin and another NSAID and 11 (22%) patients were taking neither aspirin nor a NSAID. (All patients received 150mg of aspirin the evening before surgery as DVT prophylaxis).

Results: The average pre-operative haemoglobin of the group taking aspirin and a NSAID, aspirin only and neither aspirin nor NSAID group was 12.9g/dl, 13,8g/dl and 13.49g/dl respectively. The drop between their pre-operative level and Day 3 Haemoglobin level was 3.788g/dl, 4.45g/dl and 4.28g/dl respectively.

The same trend was reflected in the PCV drops of 0.111, 0.133 and 0.1273 respectively. Transfusion rates for the three groups showed that those on aspirin and another NSAID had the highest rate with an average of 0.235 units per patient compared to 0.136 for those on aspirin only and 0.10 for those on neither aspirin nor NSAID.

Discussion: These findings indicate that the ingestion of aspirin or a NSAID preoperatively does not increase the amount of blood loss following total knee arthroplasty (TKA). The higher transfusion rates in the aspirin and NSAID group is because of the lower preoperative haemoglobin as compared to the other groups studied.

Conclusion: Observation of transfusion trends within our unit has shown a transfusion rate of 18% in patients with a preoperative Haemoglobin level of greater than 13.0g/dl as compared to 48% with a haemoglobin level of 13.0g/dl or less (review of 180 consecutive patients undergoing Total Knee Arthroplasty).

The ingestion of aspirin and NSAID does not increase blood loss following TKA but significantly have a lower preoperative Hb level. We feel that pre-operative Haemoglobin levels are the best predictors of transfusion requirements following total knee arthroplasty.

Introduction: Surgical injury induces a systemic inflammatory response proportional to the severity of the insult. An appropriate response maintains homeostasis and allows wound healing while an excessive response may trigger an inflammatory cascade resulting in the systemic inflammatory response syndrome (SIRS). Tissue injury results in cytokine release, which in turn stimulates the production of acute phase proteins such as C-reactive protein (CRP), fibrinogen, complement C3 and haptoglobin. Serum CRP levels rise following total hip arthroplasty (THA), peaking on the second to third post-operative day. Local effects of the inflammatory response manifest as the cardinal signs of inflammation, which include swelling.

One of the potential benefits cited for minimally invasive THA is reduced soft tissue trauma resulting in less post-operative pain, less swelling and earlier mobilisation. Objective evidence, from well designed prospective studies, for these benefits remains lacking. The aim of this study was to investigate whether a minimally invasive technique in THA results in a reduced acute phase response and reduced post-operative swelling compared to THA performed through a standard incision of 16cm.

Materials and Methods: 219 patients were randomised to either a minimally invasive (less than or equal to 10cm) or standard (16cm) incision group. Patients were blinded to their incision length. Anaesthetic and postoperative analgesic protocols were standardised. A single surgeon performed all operations using an uncemented cup and a cemented stem. Baseline CRP levels were measured pre-operatively and re-measured on the second post-operative day to determine whether there was any difference in the magnitude of the inflammatory response between the two patient groups. Pre-operative measurements were also made of the mid-thigh circumference on the affected side. The mid-thigh circumference was re-measured at 48 hours to assess postoperative swelling.

Results: There was no statistically significant difference in the mean serum CRP levels at 48 hours, which were 135.7mg/L (SD 51.2) for the mini-incision group and 125.6mg/L (SD 59.4) for the standard group (p=0.20). With respect to post-operative swelling, the mean increase in mid-thigh circumference at 48 hours was 4.3cm for the mini-incision group and 3.7cm for the standard group. The difference between the two groups was not statistically significant (p=0.30)

Conclusion: THA performed through a single incision minimally invasive approach does not result in reduced post-operative swelling or a reduced acute phase response, as measured from post-operative CRP rise, compared to THA performed through a standard incision of 16cm.

Introduction: Historically, it has been accepted that the pain associated with arthritis of the hip is usually located in the groin, anterior and lateral thigh with occasional radiation to the anterior knee. Patients complaining of thigh pain that extends below the knee are often considered to have a degenerative lumbar spine as the cause for their lower limb symptoms and total hip replacement (THR) may not be offered.

Following review of data regarding the preoperative distribution of pain in 2000 patients attending for hip replacement, it was noted that 40% of these patients had complained of pain at or below the knee.

We proposed to prospectively investigate the severity and location of pain in patients attending for THR and assessed how this distribution of pain altered following surgery. We also proposed to examine the distribution of radiological wear preoperatively and assess if there is any relationship between localisation of pain, and the severity or distribution of the radiological wear pattern.

Methods: 200 consecutive patients undergoing primary THR completed a questionnaire regarding the location and severity of their pain. Pain was localised to one or more of nine areas extending from low back to the foot. The localisation of pain was quantified as to severity using a visual analogue score. Questionnaires were completed both 4 weeks preoperatively and subsequently at a 3-month review clinic.

All patients underwent a standardised preoperative AP and Lateral x-ray. The AP film was divided into three areas, and the lateral film was divided into 5 areas. Each zone was assessed as to the severity of wear pattern and graded from 1–3 (no change in joint space, decreased joint space, femoral or acetabular destruction).

Results: The 200 patients complained of pain in a total of 980 areas preoperatively and 105 areas postoperative. 70% of the patients had complete relief of all pain at 3 months. The most common area of pain identified by patients was to the anterior aspect of the knee (82%), followed by pain at the greater trochanter and groin. 55% patients complained of pain extending to below the knee, mostly over the anterolateral aspect of the leg. Only 7% of these patients continued to complain of any below knee pain postoperatively, and all of these patients still had some relief of their below knee pain at review.

With regard to the frequencies and severity of x-ray changes, zone-1 (34%) was most commonly severely damaged with femoral and/or acetabular destruction in the AP film, with the anterior and anterolateral areas being most commonly affected areas in the lateral film (20% and 19% respectively).

When the distributions and severities of x-ray changes were correlated with the distribution of pain localised pre and postoperatively we were unable to show any association between the degree of radiological wear in any one zone and the locatin of pain identified by the patient. In fact, there was a normal distribution to the severity of radiological damage between each of the zones and localisation of pain in any of the 9 areas.

Conclusions: A significant number of patients who require hip arthroplasty have pain extending below the knee. This pain is frequently relieved following THR. The commonest area of sever hip joint wear with loss of femoral or acetabular bone is antero-superiorly. It is important to recognise this during surgery, such that action can be taken to ensure appropriate reaming such that subsequent correct tissue tension and leg lengths are achieved. We are unable to show any relationship between area of pain and area of radiological degeneration. We believe that patients who complain of pain in their back, buttock or thigh, which extends below the knee, can still benefit from total hip replacement. Patients who attend complaining of low back pain with radiation of pain down their leg should have their hips as well as their lumbar spine examined and imaged. Careful consideration should be taken before labelling the paid as being referred from degenerative back disease.

Introduction: It has been shown that acrylic bone cement is weakened by its porosity, which enhances the formation of micro-cracks that contribute to major crack propagation. It has also been observed, that mixing procedures play a significant role in determining the quality of bone cement produced. A high degree of porosity is found to exist in cement that is inadequately mixed.

Currently mixing system allow for the preparation of the bone cement under the application of a vacuum in a closed, sealed chamber by means of a repeatable mixing action. These systems are perceived to be repeatable, reliable, and operator independent. The objective of this study is to evaluate the quality and consistency of acrylic bone cement prepared by scrub staff in an orthopaedic theatre using a commercially available third generation vacuum mixing syringe, in terms of the level of voids within the cement microsturcture.

Materials and Methods: The mixing devices were stored at 23°C ± 1°C for a minimum of 24 hours prior to mixing. The acrylic bone cement (Palacos R® with gentamicin, Biomet Merck, UK) was stored at 4°C ± 1°C for a minimum of 24 hours prior to mixing.

Bone cement was mixed using a commercially available third generation mixing device (vacuum = −550mmHg) at Musgrave Park Hospital, Belfast, Northern Ireland. The cement was mixed according to the device manufacturers’ instructions for use. Mixing was carried out during a joint replacement surgery by a number of experienced theatre scrub staff (n = 35). The cement remaining at the end of the procedure was allowed to cure within the delivery nozzle, made from linear low-density polyethylene (LLDPE) and having an internal diameter of 10mm. 205 nozzles were collected post-operatively and stored at 23°C ± 1°C prior to testing. The percentage porosities were determined by measuring the apparent densities based on Archimedes principle and, as a direct result; it was possible to calculate the mean percentage porosities.

Discussion: It can be observed that the majority of the theatre nurses, ie 46.8% prepared bone cement using the vacuum mixing system containing a porosity of between 2% to 4%. A cement porosity of this range would be the accepted optimum content for acrylic bone cement. However, 6.4% of the theatre nurses prepared cement demonstrating a porosity content ranging from 8–16%, which is highly unsatisfactory when you consider that the cement mixing system is perceived to be a consistent and reliable mixing device that is operator independent.

Figure 2 illustrates a bar chart representing the bone cement porosity as a function of which orthopaedic theatre the cement was prepared. There was no significance difference when comparing the quality of the cement mixed in terms of porosity with the different theatres. The mean porosity values of the cement mixed ranged between 2.5% and 5.2% depending on which theatre was used.

Conclusions: Bone cement mixed using the commercially available third generation device in theatre by 35 scrub staff was found to have a high degree of variability. Thus demonstrating that even an alleged reproducible mixing system is independent on mixing technique when used in a clinical situation by a number of users. Thus illustrating the system is not wholly user independent.

As a consequence of this investigation it is recommended that the key to ensuring high quality bone cement, with a good mechanical strength, that can be consistently prepared in theatre by scrub staff are two fold.

The orthopaedic staff must be aware of the significance of cement mixing and how it is affected by a number of factors including the type of mixing system, vacuum level applied, and mixing technique.

Introduction Range of motion (ROM) is an important measure of outcome. A better understanding of the factors influencing ROM is important when counselling patients undergoing TKA.

Aim The aim of the study was to prospectively evaluate the influence of a number of selected variables on knee flexion at one year using the same prosthesis in a single surgeon series.

Patients and Methods 170 patients (57 males; 113 females) undergoing TKA were prospectively evaluated. The following data was recorded for each patient: age, gender, primary diagnosis, direction and magnitude of the preoperative axial deformity, BMI, cement use, preoperative and one year Oxford Knee Scores (OKS), the active and passive range of motion (ROM) preoperatively, at the end of surgery and at three month and one year review.

Results Average flexion values at each stage were as follows: preoperative (1110), end of surgery (1200), three months (1030) and one year (1070). There was a significant loss of flexion following TKA. The improvement between three months and one year however proved significant. Multiple regression analysis revealed that preoperative flexion was the strongest predictor of one-year flexion. Increasing age was also found to have a significant influence on final flexion. Gender, BMI, pre-operative OKS and cement use had no significant influence on final flexion. Patients tend to migrate towards a middle range of flexion i.e. those with poor flexion gain movement whilst those with good flexion tend to lose motion.

Conclusions Preoperative flexion is the strongest predictor of final flexion following TKA.

Introduction Fixed flexion deformity (FFD) represents a challenge during total knee arthroplasty (TKA). Furthermore, controversy exists as to the fate of FFD following TKA.

Aims The aims of this study were to determine how fixed flexion behaves in relation to surgery, factors that may influence or correlate with FFD both preoperatively and following TKA and the effect of FFD on outcome at one year.

Patients and Methods 133 patients (41 males; 92 females) undergoing TKA were prospectively studied. The following data was recorded for each patient: age, gender, primary diagnosis, direction and magnitude of the pre-operative axial deformity, BMI, preoperative and one year Oxford Knee Scores (OKS), the active and passive range of motion (ROM) preoperatively, at the end of surgery and at three month and one year review. FFD was defined as forced passive extension (FPE) greater than zero degrees.

Results Sixty-six patients (50%) had a preoperative FFD (mean, 60). At the end of surgery, this measured 10, 80 at 3 months and 40 at one year. When comparing those with a preoperative FFD to those with no FFD, there was no significant difference when assessing age, BMI or preoperative OKS. Preoperative FFD was significantly more common in males although there was no significant difference in the magnitude of FFD at any stage between males and females. There was a significant improvement in FFD at one year. Patients with a preoperative FFD were found to have significantly less flexion both preoperatively and at one year. When comparing those with FFD at one year to those with no FFD, those with FFD were significantly older and had significantly less flexion. There was no significant difference in BMI, OKS or gender.

Conclusions There is a definite trend when assessing the change in FFD with time. Correction at the time of surgery would appear to be important. Residual FFD is associated with reduced flexion at one year.

Purpose: The study objective was to measure ‘posterior condylar offset’ (PCO) following Low Contact Stress (LCS) total knee arthroplasty (TKA), and determine its influence on one-year flexion values.

The term ‘posterior condylar offset’ (PCO) is defined as the distance from a line projected along the posterior cortex of the femur to the maximum convexity of the posterior condyles. Furthermore its magnitude has been found to correlate with final flexion following PCL-retaining TKA, if reduced by more than 3mm post-operatively1..

Method: We reviewed the pre and post-operative radiographs of 69 patients who had undergone primary LCS TKA. All cases were performed by a single surgeon using the same operative technique. The PCO was measured from the preoperative and postoperative true lateral radiographs. Pre-operative and one-year flexion was measured using a goniometer.

Results: Of the 69 patients studied, three patients (4%) had more than 3mm reduction in their PCO following TKA (range −4mm to −6mm). Eleven (16%) had their post-operative PCO increased by more than 3mm (range 4mm – 5mm). The remaining fifty five (80%) had their PCO restored to within 3mm either way.

Of the three patients whose PCO was reduced by more than 3mm, one had exactly the same flexion 1 year post-operatively, one had an increase of 14 degrees, and unfortunately the third died before their 1 year review.

Using regression analysis, the strongest predictor of one-year flexion for this study group was the preoperative flexion value. The difference in PCO before and after TKA had no significant influence on one-year flexion.

Conclusion: It would appear that the LCS technique permits satisfactory restoration of PCO as only 4% of patients in this study had a decrease in PCO of more than 3mm. We feel restoration of PCO is important; however in this study it did not have significant influence on final flexion.

Introduction Satisfactory patellar tracking is important following total knee arthroplasty. A lateral retinacular release may be required to correct patellar maltracking but can be complicated by damage to the skin, soft tissues or patella.

Aim The aim of this study was to determine if, when using the LCS prosthesis, the rate of lateral patellar release was reduced by centering the finishing guide on Whiteside’s line as opposed to the mid-point of the femoral condyles.

Patients and Methods One hundred and ten consecutive patients (64 female, 46 male) undergoing primary total knee arthroplasty were prospectively studied. At the time of performing the champher cuts, the finishing guide was first centered on the mid-point of the femoral condyles and a mark placed on the trochlea using the needle diathermy. The finishing guide was then finally centered on the previously marked Whiteside’s line. The distance between the two marks was measured using a caliper. Following component insertion patellar tracking was checked. If required a lateral release was performed allowing the patella to track with its medial facet in contact with the medial femoral condyle.

Results Centralization of the femoral component on Whiteside’s line instead of the mid-point of the femoral condyles lateralized the component by an average of 2.7mm (range, x–ymm). This parameter was termed the patellofemoral offset (PFO). When compared to a sample of patients where the finishing guide was centered on the mid-point of the femoral condyles, the lateral patellar release rate was reduced from 25% to 18%.

The magnitude of PFO increased with age however there was no significant difference in PFO between males and females. The PFO was significantly greater for knees with a preoperative valgus deformity (p=0.006).

Conclusion Centering the femoral component on White-side’s line leads to a reduction in lateral patellar release rate during TKA.

Introduction: The anatomy of the proximal femur is an important factor in the design of uncemented femoral prostheses for which the quality of fixation and the associated bony remodelling depend on the primary stability and optimal transmission of forces to the proximal femur. This study looks at the variation in the diameter of the proximal femur with age and sex in a homogeneous population.

Materials and Methods: We studied standardised pre-operative antero-posterior radiographs of the proximal femur of 2,777 patients who have undergone total hip arthroplasty using a custom implant over a 10 year period. The radiographs were corrected for magnification and a measurement made of the endosteal diameter at the narrowest point of the proximal femur. These measurements were used in the design and manufacture of the custom femoral implant.

Results: Of 2777 patients, 1588 were female and 1189 male. The mean age for females was 69.9 years (Range 30–92) and for males 67.2 years (Range 34–92). The mean proximal femoral canal diameter was 12.67mm for females and 13.36mm for males.

The mean diameter of the proximal femur increased from 12.99mm in males less than 60 years to 13.47mm in those of over 60. This increase was not statistically significant (p-value 0.064, 95% CI). In females there was a statistically significant increase in the mean diameter from 11.38mm in the under 60 age group to 12.90mm in those over 60 ( p-value 0.000, 95% CI).

Conclusions: The increase in the diameter of the proximal femur with age especially in females presents a significant challenge to the design and long-term survivability of uncemented femoral components. This is more so when viewed against the already good long term results available for cemented femoral implants.

We report a series of 668 patients (699 hips) with an average follow up of 10.5 years (range, 10–11 years) following THR using a cemented custom-made titanium femoral stem and a cemented high-density polyethyl-ene acetabular component. The fate of every implant is known.

The mean age at operation was 68 years (24 – 94 years). The indication for THR was as follows: primary OA (629), RA (18), AVN (10), intracapsular femoral neck fracture (5), Perthes disease (3), developmental hip dysplasia (2) and SUFE (1). The mean pre-operative Harris Hip Score was 19 (range 10 – 42).

One hundred and seventy-four patients (26%) were deceased at the time of their 10-year review. Four hundred and ninety-four patients were subsequently reviewed of which 88 patients (13%) were assessed by telephone review as they were too frail to attend.

The average 10-year Harris Hip Score was 92 (range 43 – 100). The average 10-year Oxford Hip Score was 19 (range 12 – 46). 99.2% reviewed at 10 years stated that they were satisfied with their THR.

Revision surgery occurred in 21 cases (3%). Seventeen femoral components were revised for infection, one for recurrent dislocation and one was iatrogenically loosened during socket revision. There were no cases of revision for aseptic loosening of the stem. Dislocation occurred in 18 cases, of which 4 became recurrent (0.6%). Six patients had a postoperative sciatic nerve palsy (0.9%) with 4 making a full recovery. There was one case of femoral nerve palsy. Eleven patients developed a DVT (1.6%). Six patients had a PE (0.9%) all of which were non-fatal. There were 16 deep and 3 superficial wound infections. Thirty-eight patients had symptomatic trochanteric bursitis post-surgery.

In conclusion, the 10-years results of the custom femoral stem are encouraging with an overall high level of patient satisfaction.

Introduction: The use of minimal incision THR is increasing. The purpose of this study is to determine the effects of a change in operative technique from a standard incision to a minimally invasive incision at primary THR on peri-operative blood loss, analgesia requirement, length of stay, and complication rate. Two consecutive groups are compared.

Materials and methods: All patients who underwent a primary THR (posterior approach) by the senior author during a 3month period before and after a change in technique from a standard to a minimal incision were identified. 202 patients were analysed: 105 standard incisions and 97 minimal incisions. A retrospective chart review was used to collect age, height, weight, BMI, diagnosis and length of stay for each patient. Estimated peri-operative blood loss in units of blood was calculated by a validated formula. Morphine usage by PCA in the first 24hours post-operatively was recorded. Complications were identified.

Results: There was no significant difference in the mean age, height, weight or BMI between the 2 groups. Predominant diagnosis was primary osteoarthritis. Mean wound length for the standard incision was 16.6cms. Mean wound length for the minimal incision was 11cms. There was no difference in length of stay, mean 5.4days. There was no difference in morphine usage by PCA in the first 24hours, mean 39.4mgs.

Average estimated peri-operative blood loss for the standard incision group was 3.45 units and for the minimal incision group was 3.05 units (statistically significant, p-value 0.039, 95%CI). One patient after minimal incision had a superficial wound infection, which responded to oral antibiotics. There was one dislocation (standard incision).

Conclusions: Peri-operative estimated blood loss was less with a minimal incision but there was no difference in length of stay or analgesia requirement. A prospective RCT is now underway to determine the clinical efficacy of minimally invasive THR.

Leg-length inequality is not uncommon following primary total hip arthroplasty and can be distressing to the patient. An excellent clinical result with respect to pain relief, function, component fixation, range of motion and radiographic appearance can be transformed into a surgical failure because of patient dissatisfaction due to leg-length inequality.

Postoperative leg-length discrepancy was determined radiographically for 200 patients who had had a primary custom total hip arthroplasty. In all cases the opposite hip was considered to have a normal joint center.

The femoral component was designed and manufactured individually for each patient using screened marker x-rays. A graduated calliper was used at the time of surgery to control depth of femoral component insertion. The transverse acetabular ligament was used to control placement of the acetabular component and therefore restore acetabular joint center.

Using this method 94% of subjects had a postoperative leg-length discrepancy that was 6mm or less when compared to the normal side (average, +0.38mm). The maximum value measured for leg-length discrepancy was +/−8mm.

We describe a simple technique for controlling leg length during primary total hip arthroplasty and propose an alternative radiographic method for measuring leg-length discrepancy.

Objective: It is unknown whether routine physiotherapy is of benefit following total knee arthroplasty. Referrals are usually made by the inpatient physiotherapist or by the General Practitioners concerned about the patients range of knee motion. There have been no prospective, randomized, controlled studies in this area.

Design: One hundred and fifty patients undergoing primary total knee arthroplasty were recruited and randomly assigned into two groups. Ethical approval was given by the local ethics committee. Group 1 (n=55) received nine sessions of physiotherapy over a six-week period within 3 weeks of hospital discharge. Group 2 (n=76) received no outpatient physiotherapy. All patients received inpatient physiotherapy for the length of their hospital stay. Range of knee motion was measured using a goniometer by members of the outcome team blinded to the randomisation. Validated knee scores, Oxford knee, American knee society, and Bartlet patellar score were also collected. An SF-12 health questionnaire was used as a generic outcome measure.

Results: Both groups were equally matched in age, sex, diagnosis, and magnitude of deformity. Patients in Group 1 achieved an average loss in active range of motion of 2 degrees, whereas those in Group 2 achieved an average increase of 5 degrees. There is a significant difference in active range of motion between group 1 and group 2 (P=0.049). No difference in passive range of motion.

Conclusion: We concluded that the use of outpatient physiotherapy improves the range of knee motion to patients after total knee replacement at three months.

Introduction: Patellar management and related complications remain a major concern in total knee arthroplasty. Multiple problems can ensue in both resurfaced (fracture, loosening) and non-resurfaced patellae (pain).

Objective: We aim to evaluate the impact of secondary patellar resurfacing in patients with patellar related anterior knee pain having undergone a mobile bearing primary total knee arthroplasty without resurfacing.

Materials and methods: 2950 primary LCS mobile bearing total knee arthroplasties without patellar resurfacing were carried out between March 1992 and March 22003 by the senior author. Twelve patients underwent secondary patellar resurfacing for patellar related anterior knee pain. There were equal numbers male and female with a mean age of 72.1 years. There was a mean time of 27.9 months to secondary resurfacing procedure. We evaluated both clinical and radiological outcomes of this procedure.

Results: 0.4% patients required a secondary procedure. Only 3 had an unequivocal improvement in their symptoms. No morbidity was noted from the procedure.

Conclusions: The success rate of secondary patellar resurfacing is poor and we feel if this is to be offered to the patient for ongoing patellar related anterior knee pain that they be counseled carefully.

Dislocation is a recognised complication following the posterior approach in total hip arthroplasty. The senior surgeons involved in this study had routinely repaired the short external rotators and capsule by directly suturing ‘tendon to tendon’ and ‘capsule to capsule’ using No 1 Vicryl®. Over a two-year period this had no impact on the incidence of dislocation as compared to “no soft tissue repair” that had been done historically. In order to assess the effectiveness of ‘soft tissue to soft tissue’ repair fifteen patients were assessed using radiographic markers inserted during surgery. In 14 of the 15 patients the repair was found to have failed by the time of the post-operative x-ray which was taken on day 3 to 5. Since then we have changed the repair so that the capsule and rotators are reattached to bone with No 5 Ethibond® using drill holes in the trochanteric region. This modification was evaluated using the same method. Of 15 patients in the second type of repair only 2 showed a failure of repair on the post operative X-ray. This appears to be a more secure form of repair. The impact of this on the incidence of dislocation is being evaluated.

We performed a prospective clinical study in order to assess the effectiveness of repair of the short hip rotators, divided in the course of total hip replacement by the posterior approach, by the use of radio-opaque markers.

Fifteen patients, each with a diagnosis of osteoarthritis of the hip, were selected consecutively from a single surgeon’s operating list. Uncemented Duraloc® acetabular components and custom made cemented femoral components were implanted via the posterior approach in all patients.

Following implantation, the capsule and the short rotator tendons were sutured on to tendinous soft tissue around the greater trochanter using No 1 Vicryl. One radio-opaque marker clip was attached to the short rotators and capsule and a second marker was attached to the greater trochanter.

Standard antero-posterior pelvic X-rays were taken at three to five days post-operatively, and at three months following surgery. Significant separation of the radio-opaque markers in fourteen of the fifteen patients was demonstrated on the day three to five X-ray, indicating failure of the repair.

We conclude that this soft tissue repair is unsatisfactory. It may be of value to develop a more effective repair technique, with the overall aim of reducing total hip replacement dislocation, and as such we are currently investigating a soft tissue to bone repair.

Introduction: Wear, and the resultant loosening and revision, of Total Hip Replacements (THRs) remains the limiting factor in the long term success of the prosthesis. Over 1 million Total Hip Replacements (THRs) are implanted each year, of which about 15% are revisions, most of which are a consequence of loosening of either femoral or acetabular components. This is frequently caused by either the mechanical (Wroblewski, 1986) or biological (Besong et al, 1997) response to the wear of ultra-high molecular weight polyethylene (UHMWPE) acetabular component.

In a previous study Bennett (2002, 2000) has demonstrated that the walking patterns of THR patients 5 years post operation directly correlated with the wear of the acetabular component, as measured radiographically. The present study considers THR patients 10 years post-operatively, ensuring more accurate wear measurements and more meaningful outcome measures.

Materials and Methods: Gait Analysis was performed on a number of THR patients following routine review using a Vicon 370 data capture system and a lower body marker set. This data was processed using Polygon software and joint angles were derived for the hip in the sagittal, coronal and transverse planes. A computer simulation was used to determine the path which each of 20 points on the prosthetic femoral head traces on the acetabulum during walking.

Results: It was found that patients exhibited different patterns of movement ranging from liner to multi-directional. Normal subjects have previously been found to exhibit multi-directional movement. Patients with mult-directional movement showed evidence of greater wear (Bennett et al., 2000).

Discussion and conclusion: Linear movement causes orientation hardening and wear resistance while multi-directional movement cause increased shear and greater wear rates. These differences in movement loci have a significant influence on UHMWPE wear rate and the long term survival of the implant.

Venous stasis is identified in Virchow’s triad as one of the risk factors leading to deep venous thrombosis (DVT). Preventing or reducing stasis during the peri- and post-operative states should minimise the risk of DVT. We have investigated the efficacy of a new device (Waveform, Amtec Medical Ltd), employing electrical calf stimulation to promote venous return in patients (n=18, mean age 67.2±7.9yrs) presenting for total hip replacement arthroplasty. The device placed over the soleus muscle, offers various levels of stimulation (70–90V) at six second intervals. Duplex ultrasound imaging was used to locate and measure venous flow in the popliteal vein. Velocity measurements were recorded at three time intervals: before (baseline) and after induction of spinal anaesthesia, and finally in response to electrical stimulation. Results showed that immediately following spinal anaesthesia there was an increase in venous flow velocity from the baseline by a factor of 2 (from 9.2cm/s to 17.2cm/s). Furthermore, each activation of the electrical stimulus caused an increase in flow velocity by on average a factor of 4.4 over pre-stimulus flow (8.6cm/s to 39.8cm/s). These data compare favourably with previous observations using the Belfast calf stimulator and demonstrate the effectiveness of electrical calf stimulation as a method of preventing venous stasis in the lower limbs during surgery.

In Britain 8 million people consult their general practitioner annually with musculoskeletal conditions leading to referral of 1.5 million patients to Orthopaedics/ Rheumatology. Northern Ireland has the highest waiting lists for outpatients in Britain. The demand on orthopaedics continues to rise despite past attempts to reduce waiting lists. Trauma and orthopaedics accounted for 14% of the excess waiters for outpatients at June 2002. (DHSSPS Sept 2002) Roland et al 1991, etc. demonstrated that 43% of all orthopaedic referrals were inappropriate. In Belfast, G.P.s and Physiotherapists in partnership with the Regional Orthopaedic Service decided to pilot a Primary Care Orthopaedic Triage Service. The vast majority of orthopaedic referrals relate to three main body parts: lumbar spine 28%, knees 34% and hips 25% and these were chosen to be triaged for the pilot. Approval was sought and granted from Queen’s University Belfast Ethics Committee.

Phase 1 involved the training of 2 GPs and 2 physiotherapists at the Musgrave Park and Royal Victoria Hospital with the full cooperation of the orthopaedic surgeons.

Phase 2 tested independently the diagnostic capability of the trained professionals and assessed the appropriateness and management of orthopaedic referrals against the consultants decision as ‘gold standard’.

95 patients participated in the study.

55.8% of referrals were deemed appropriate by the consultants, compared to 44.6% by the GP/physio team. The Kappa statistical score was 0.79 reflecting a good level of agreement and is comparable to other clinical specialties (Sackett 1991). The sensitivity of the trained professionals on orthopaedic referrals was 83% and the specificity was 97%. Kappa value for management of inappropriate referrals was 0.83.

Orthopaedic referral can be acceptably triaged by primary care professionals reducing the number of onward referrals to outpatients by 40% and increasing the appropriate referrals from 56% to 97%.

Introduction: Historically, it has been accepted that pain associated with arthritis of the hip is usually located in the groin and thigh with radiation to the anterior knee. However pain below the knee, and into the foot was not believed to be associated with arthritis of the hip. Patients complaining of thigh pain that extends below the knee are often considered to have a degenerative lumbar spine as the cause for their lower limb symptoms, and hip arthroplasty may not be offered. We examined the severity and location of pain in patients attending for arthroplasty and assessed how this altered following surgery.

Methods: 200 consecutive patients undergoing primary total hip arthroplasty completed a questionnaire regarding the location and severity of pain in the leg and also an Oxford hip score to assess functionality. These were completed approximately 4 weeks preoperatively and again at a 3-month review clinic.

Results: 57% (114/200) of patients complained of pain below their knee preoperatively. Only 9% (10/114) of these patients continued to complain of pain postoperatively, and of these patients their mean pain score decreased by 44% (9 to 5). Only 1% (2/200) of all patients complained solely of pain in the knee or more distally, and both of these had complete relief of pain 3 months postoperatively.

Conclusion: A significant number of patients with degenerative hip disease have pain below the knee. Patients who complain of pain in their back, buttock or thigh, which extends below the knee, may still benefit from total hip replacement. Careful consideration should be taken before labelling the pain as being referred from degenerative back disease.

Thirty-one patients (33 knees) with symptomatic patello-femoral osteoarthritis and minimal tibiofemoral changes underwent LCS total knee replacement without patellar resurfacing.

Average age was 73 years (range, 58–89 years) with a female to male ratio of 5:1. Average follow-up was 20 months (range, 12–40 months). All except four patients had grade 3 or 4 patello-femoral osteoarthritis.

Preoperatively all patients had significant knee pain. Sleep disturbance was reported in 21 patients. All but 10 patients required walking aids. Average range of motion was 1080 (80–125).

At latest review, 21 knees are pain-free, the remaining 12 knees describing only occasional knee pain. Two patients continue to have night pain. Average range of motion was 1040 (70–1350). Lateral patellar tilt improved in all but five knees by an average of 70 (1–260). Patellar congruency improved in all but three knees by an average of 18% (3–63%). None of the patients to date have required revision surgery.

We suggest that knee arthroplasty without patellar resurfacing is an effective option in older patients with isolated patello-femoral osteoarthritis.

In terms of function, range of movement is an important measure of outcome.

The purpose of this study was to determine whether or not stripping the capsule of the distal femur at the time of primary total knee arthroplasty had a significant effect on the range of knee movement achieved at the end of the operation. An improvement of 5 degrees or more was considered significant.

One hundred and twenty-five patients (47 males; 78 females) presenting for primary total knee arthroplasty were recruited. All operations were performed by the senior author using the LCS rotating platform system without patellar resurfacing.

Preoperatively, the tip of the greater trochanter, the lateral femoral epicondyle and the anterior border of the lateral malleolus were marked. Using a digital camera, images of the limb proposed for surgery were taken with the knee in extension, forced extension, flexion and forced flexion. Camera set up was standardised for all photographs.

Using a random numbers program, patients were randomised either to have release of the posterior knee joint capsule or not. The surgeon was informed at the time of the operation.

At the end of the procedure the digital images were repeated. Total arc of knee movement preoperatively ranged from 41° to 161° (average, 115°). Postoperatively, this varied from 95° to 157° (average, 124°).

Average arc of knee movement was 125° for the no release group and 123° for the released group. Of the 78 patients where the increase in total arc of knee motion was significant, 41 had been released and 37 had not. No statistically significant difference was noted.

In conclusion, we report that releasing the posterior capsule of the knee joint routinely during primary total knee arthroplasty conveys no significant advantage in terms of the range of knee motion achieved immediately following surgery. Consequently, it is unlikely to increase the long-term range of movement.

Introduction: There is increasing awareness and concern among the medical profession, general public and media about the various complications of homologous blood transfusion.

Primary arthroplasty of either the hip or knee has an estimated total bleeding of 1.51 (Lotke et al 1991), commonly resulting in transfusion. In knee arthroplasty, performed with the use of a tourniquet, almost all the bleeding occurs postoperatively. Several studies have shown that salvage of blood after the operation and reinfusion can reduce the need for homologous transfusion (Majkowski RS et al, Newman JH et al).

We studied prospectively 100 consecutive patients for knee replacement to compare post-operative transfusion requirements in blood salvage and reinfusion group and a no drain technique.

Methods: After written consent 100 consecutive patients for knee replacement surgery were randomly allocated by computer generated numbers to either the no drain group (n=50) or the reinfusion group (n=50). The patients were anaesthetised as deemed appropriate by their anaesthetist. All the patients were operated on using a tourniquet. At the end of surgery the wound was closed with or without a deep drain. The drain was attached to the Constavac CBC II closed suction system. Preoperative haemoglobin and haematocrit values were recorded. Homologous blood was transfused to the patients as per the standard protocol depending on the haematocrit and or haemoglobin at 4 & 8 hours post-operatively, as well as days 1,2 & 3. In the reinfusion group blood collected in the reservoir was transferred to the blood bag and reinfused at 5 hours or 500 mls depending which was earlier. At 8 hours the reservoir blood was collected and reinfused, no more blood was reinfused as per the manufacturer recommendations. Cardiovascular stability was assessed by hourly blood pressure and heart rate during the first 24 hours and twice daily thereafter. Blood loss was assesses by measuring the drain loss, assessing the wound ooze serial haematocrits and total transfusion requirements.

Results: 50 patients were completed in each group. The mean preoperative haemoglobin in the drain group was 12.8 g/dl and in the no drain group it was 12.9 g/dl. No difference in predisposing factors for bleeding was recorded in the two groups. The mean volume of blood collected in the drain group was 1008mls and the mean volume of autologous transfused was 864 mls. 14% of patients in both groups had no requirement for homologous blood. There was no significant difference in the homologous blood transfusion in the two groups over the study period (up to day 3 post op), the no drain group requiring and average of 2.1 units of packed cells the reinfusion group requiring an average of 1.8 units of packed cells in total. The homologous blood requirements in the drain group was significantly reduced on day 2 in comparison to the no drain group, but as noted there was no overall reduction in homologous requirements. Cardiovascularly 16% of patients with a drain had at least one episode of hypotension (Bp < 90 systolic) compared with 20% of patients in the no drain group. The group without a drain had a significant increase in wound ooze (70% compared with 44%)

Conclusion: Post-operative blood salvaging and autologous transfusion following primary knee replacement under tourniquet in this study did not significantly reduce the patient’s requirement for homologous blood transfusion in the first 3 days post operatively. There was a significant increase in wound ooze in the no drain group but as shown this has not result in an increase in cardiovascular instability or an increase in transfusion requirements.

The detection and recording of vibration emission from human joints, a technique which we have termed "vibration arthrography", is a sensitive, non-invasive method for the objective study of the locomotor system. Using vibration sensors attached to bony prominences around the knee, we studied the joints of both normal and symptomatic subjects. Normal subjects produced three signal types--physiological patellofemoral crepitus, patellar clicks, and the lateral band signal. In symptomatic subjects we identified and categorised many signal types and related them to pathology. Lesions of the menisci produced distinctive signals, and it was possible not only to lateralise the tear, but in many cases to determine the type of meniscal injury present. Vibration arthrography promises to be a useful tool in the non-invasive diagnosis of knee disorders.