To quantify the intraoperative cerebral microemboli load during primary total knee arthroplasty (TKA) using transcranial Doppler ultrasound and to investigate whether a patent foramen ovale influences cerebral embolic load in general.

Patients undergoing primary TKA, with no history of stroke, TIA, ongoing CNS disease or alcoholism were included. All operations were carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli l oad was recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis. Patent foramen ovale detection was performed using bolus intravenous injection of agitated saline followed by valsalva manoeuvre technique and TCD. Timing of specific surgical steps was recorded for each operation and emboli load calculated for that period.

Results: 50 TKA patients were studied (31 females, 19 males); 28 right and 22 left TKAs were performed. Cerebral microembolisation occurred in 19 patients (42%). Mean microembolic load was 3.56 per patient (range 0–21). PFO was detected in 9 patients (18%). Two thirds of PFO positive patients displayed cerebral microemboli. However, 36.6% (n=15) of PFO negative patients also displayed microemboli intraoperatively. Deflation of the tourniquet was followed by a larger microembolic load than the other phases of the operation.

Conclusion: Intraoperative cerebral microembolisation occurs in a significant proportion of patients during total knee arthroplasty. The presence of a patent foramen ovale does not appear to influence the incidence microemboli intraoperatively. Specific surgical activities are associated with generating greater embolic loads. These questions will be comprehensively assessed in the larger study currently underway.

Medial unicompartmental replacement (UKR) has been shown to have superior functional results to total knee replacement (TKR) in appropriately selected patients, and this has been associated with a resurgence of interest in the procedure. This may relate to evidence showing that the kinematic profile of UKR is similar to the normal knee, in comparison to TKR, which has abnormal kinematics. Concerns remain over the survivorship of UKR and work has suggested the anterior cruciate ligament (ACL) may become dysfunctional over time. Cruciate mechanism dysfunction would produce poor kinematics and instability providing a potential mechanism of failure for the UKR.

Aim: To test the hypothesis that the sagittal plane kinematics (and cruciate mechanism) of a fixed bearing medial UKR deteriorate over time (short to long term).

A cross sectional study was designed in which 24 patients who had undergone successful UKR were recruited and divided into early (2–5 years) and late (> 9 years) groups according to time since surgery. Patients performed flexion/extension against gravity, and a step up. Video fluoroscopy of these activities was used to obtain the Patellar Tendon Angle (PTA), the angle between the long axis of the tibia and the patella tendon, as a function of knee flexion. This is a previously validated method of assessing sagittal plane kinematics of a knee joint.

This work suggests the sagittal plane kinematics of a fixed bearing UKR is maintained in the long term. There is no evidence that the cruciate mechanism has failed at ten years. However, increased tibial bearing conformity from ‘dishing’, and adequate muscle control, cannot be ruled out as possible mechanisms for the satisfactory kinematics observed in the long term for this UKA.

Purpose: Ceramic/ceramic bearing surfaces have the advantage of significantly decreased wear and high biocompatibility compared to CoCr/PE or ceramic/PE. The purpose of this randomized, controlled, multi-center, prospective study was to evaluate the clinical and roentgenographic results of 469 ceramic/ceramic versus 321 ceramic/PE THA at a 2 to 7 year follow-up.

Methods: The ceramic/ceramic THA had a polished alumina femoral head articulating with a polished alumina acetabular liner seated into the metal acetabular shell designed to avoid any impingement of the ceramic liner on the femoral component. Evaluations were completed preoperatively, at 6 months and yearly postoperatively.

Results: Mean age of the 790 patients was 59 years, with slightly more females. There were no significant demographic differences between the two groups. The main diagnoses were OA in 74% and osteonecrosis in 19%. Preoperatively the mean Harris Hip Score (HHS) and WOMAC scores were 44 and 41, respectively, and did not differ significantly between the two groups. At follow-up, the mean HHS was 93 for the ceramic/ ceramic THA and 93 for the ceramic/PE THA. The mean WOMAC scores showed no differences at follow-up. Roentgenographic analysis revealed one acetabular cup migration with a PE liner. One ceramic liner fractured upon insertion that was not properly positioned prior to impaction. Otherwise, there were no revisions or complications related to either bearing surface.

Conclusions: This short-term study has demonstrated efficacy and safety of a ceramic/ceramic bearing surface compared to the standard ceramic/PE surface currently used in clinical practice, with no failures or complications related to the bearing surface. Further follow-up is indicated to determine the long-term outcome.

Funding : Commerical funding

Funding Parties : Encore Orthopaedics

70 patients who underwent dynamic MRI scanning for chronic anterior knee pain were retrospectively evaluated. All patients had been symptomatic for over a year. 43 patients had been treated conservatively and 27 had undergone surgical procedures (arthroscopy -13, lateral release- 9, tibial tubercle transfer 5). The extent of subluxation, tilt and cartilage abnormalities on MRI scans, during resisted extension were assessed. Functional scoring (Oxford, Lysholm and Tegner scores) was done through questionnaires and correlated with the radiological findings.

54 (77%) patients were found to have some patellofemoral abnormality on the scans. Subluxation was the most common finding with mild subluxation in 30, moderate in 18 and severe in 17 knees. Mild tilt was seen in 26 knees and moderate to severe tilt in 14 knees. Tilt was found in association with subluxation except in 8 cases. Grade 1 and 2 cartilage wear were seen in 13 knees and Grade 3 and 4 in 21 knees.

The “Tibial Tubercle to Trochlear Groove distance” (TTD) was measured in all knees and correlated with subluxation. The average distance was 13.5mm, 13.6mm and 18.8mm for mild, moderate and severe subluxation respectively. All patients with a TTD _ 20mm had moderate or severe subluxation. The specificity of a TTD _ 20mm for severe maltracking was 100% but the sensitivity was only 42%.

The TTD appears to be the single most significant parameter determining patella tracking. We have proposed an algorithm for the surgical and non-surgical treatment of chronic anterior knee pain. We recommend lateral release for those with moderate and severe subluxation and a tibial tubercle transfer as well in those with a TTD _ 20mm. The functional scores did not zshow a significant correlation with the grading of subluxation.

We report the mid-term results of a new patellofemoral arthroplasty for established isolated patellofemoral arthritis. We have reviewed the experience of 109 consecutive patellofemoral resurfacing arthroplasties in 85 patients who were followed up for at least five years.

The five-year survival rate, with revision as the endpoint, was 95.8% (95% confidence interval 91.8% to 99.8%). There were no cases of loosening of the prosthesis. At five years the median Bristol pain score improved from 15 of 40 points (interquartile range 5 to 20) pre-operatively, to 35 (interquartile range 20 to 40), the median Melbourne score from 10 of 30 points (interquartile range 6 to 15) to 25 (interquartile range 20 to 29), and the median Oxford score from 18 of 48 points (interquartile range 13 to 24) to 39 (interquartile range 24 to 45). Successful results, judged on a Bristol pain score of at least 20 at five years, occurred in 80% (66) of knees. The main complication was radiological progression of arthritis, which occurred in 25 patients (28%) and emphasises the importance of the careful selection of patients. These results give increased confidence in the use of patellofemoral arthroplasty.

There have been several reports of good survivorship and excellent function at ten years with fixed-bearing unicompartmental knee replacement. However, little is known about survival beyond ten years.

From the Bristol database of over 4000 knee replacements, we identified 203 St Georg Sled unicompartmental knee replacements (174 patients) which had already survived ten years. The mean age of the patients at surgery was 67.1 years (35.7 to 85) with 67 (38.5%) being under 65 years at the time of surgery. They were reviewed at a mean of 14.8 years (10 to 29.4) from surgery to determine survivorship and function. There were 99 knees followed up for 15 years, 21 for 20 years and four for 25 years. The remainder failed, were withdrawn, or the patient had died.

In 58 patients (69 knees) the implant was in situ at the time of death. Revision was undertaken in 16 knees (7.9%) at a mean of 13 years (10.2 to 21.6) after operation. In seven knees (3.4%) this was for progression of arthritis, in three (1.5%) for wear of polyethylene, in four (2%) for tibial loosening, in two (1%) for fracture of the femoral component and in two (1%) for infection. Two knees (1%) were revised for more than one reason.

The mean Bristol knee score of the surviving knees fell from 86 (34 to 100) to 79 (42 to 100) during the second decade. Survivorship to 20 years was 85.9% (95% CI 82.9% to 88.9%) and at 25 years was 80% (95% CI 70.2% to 89.8%). Satisfactory survival of a fixed-bearing unicompartmental knee replacement can be achieved into the second decade and beyond.

Aim: To assess the results of aseptic and aseptic cases using the PFC/TC3 system, and to correlate this with the restoration of joint line height.

Method: 148 patients underwent revision TKR using the PFC/TC3 system. No re-revision cases were included in this series. Data was prospectively collected (using the Bristol Knee Score) pre-operatively and at a mean of 4.2 years post-revision. 31 revisions were for infection and 53 revisions were for aseptic loosening. Revision for infection was done as a two-stage procedure and aseptic as a single operation. Measurements of the joint line height were made pre and post-operatively using Figgie’s method. The cases were divided into 3 groups on the basis of joint line restoration:

Lowered by more than 5 mm

Results: The mean pre-op total score for the infection group was 35/100 and 40/100 for the aseptic loosening group. The total score post-operatively was 67 for the infection group and 73 for the aseptic loosening group. The joint line was restored in 50% of infected cases and in 60% of aseptic loosening cases.

Conclusion: although the overall results were slightly less satisfactory for the infected revision group, there was no significant difference between the two groups either in total BKS scores or in reproduction of the joint line. The average outcome was much less good than for primary TKR.

Purpose: This study was carried out to compare the alteration in skin sensation following midline, medial and short medial incisions for knee replacement.

Method: 88 patients with 102 replaced knees were examined for altered skin sensation over the front of the knee, all were at least 18 months from their knee replacement. Twenty-one knees had a medial incision, 38 a midline incision and 43 a short medial incision for UKR.

A scale of −2 to +2 was used to measure different degrees of skin hypo or hyperaesthia. A purpose-designed grid, designed to fit different knee sizes, was used to record sensations. A computer programme was created to record all patients’ data including the length and shape of the incision in relation to anatomical landmarks.

A parallel histological study was carried out on 18 skin specimens taken from the 2 standard incisions. The specimens were prepared and stained for nerve endings. The number of nerve endings in each incision was calculated.

Results Histologically, less cutaneous nerve endings were seen in specimens from midline incisions than medial incisions.

Discussion: Altered skin sensation is unpleasant to many patients at least initially and may affect function especially kneeling. The midline line incision seems to produce less dermal parasthesia than the medial incision, this probably relates to both the wound position and the density of nerve endings. As expected, the length of incision correlated with the area of numbness when comparing short and long medial incisions.

Purpose of study: To examine the fate of the non operated on compartment of the knee, following unicompartmental knee replacement (UKR), by radiological assessment 10 years after operation.

Summary of methods and results: A total of 50 UKRs were performed on 45 carefully selected patients between 1989 and 1992. Fifteen patients died, two patients were lost to follow-up and two knees were revised. The radiographs of the remaining 30 knees were reviewed three times by blind and randomised assessment using Ahlback and Altman scoring systems to measure the progression of osteoarthritis within the joints. Standard long-leg weight-bearing anteroposterior views of the knee and skyline views of the patello-femoral joint were taken before, at eight months and ten years after operation. Two knees showed evidence of progression of osteoarthritis within the patello-femoral joint and three knees showed some progression of the opposite tibio-femoral compartment.

Statement of conclusion: Our study provides evidence that after ten years progressive OA within the retained compartments following UKR is rare and usually minor.

Introduction: This study assesses the prevalence of trochlear dysplasia as a cause of patello-femoral arthritis (PFOA), though for many years the condition was scarcely recognised and not recorded.

Method: Since 1989 385 primary isolated patello-femoral replacements have been performed in Bristol for patello-femoral arthritis.

The diagnoses recorded were:

Lateral facet PFOA 227

Symmetrical PFOA 95

Medial facet PFOA 24

Dislocation 15

Subluxation 33

Post traumatic 6

Trochlear dysplasia was noted either retrospectively or as “other diagnosis” in only 10 cases between 1989 and 2003, however in the last year, the condition became recognised locally, and has been recorded in 11 of the 48 cases performed.

A recent review of 40 cases aged under 55 showed evidence of causative trochlear dysplasia in more than 50%.

This was based on:

Trochlear dysplasia recorded on operative note 8

A positive crossing sign on a true lateral xray 19

A sulcus angle > 144° 20

Conclusion: Trochlear dysplasia frequently leads to severe symptomatic patello-femoral arthritis, often at an early age, and can be helped by isolated patello-femoral replacement. Since only 38 of the 385 cases had undergone re-alignment procedures it seems likely that the condition initially presents in a variety of ways.

Introduction: Correct prosthesis alignment and joint line reproduction in total knee replacement (TKR) is vital for a successful clinical outcome. It is acknowledged that the ideal coronal alignment of the knee following TKR should be between 4–10 degrees of valgus. A neutral or varus knee is associated with a higher failure rate. Previous studies have shown that ideal alignment is achieved in only around two-thirds of cases.

Joint line elevation > 8mm has been associated with inferior clinical outcome, and depression associated with retropatellar pain and increased risk of patella subluxation.

Recently, modifications have been made to the Kine-max-Plus Total Knee System instrumentation, theoretically providing better internal fixation to prevent a varus cut and a 12 mm measured resection from the “normal” tibial plateau. This study aims to examine whether these changes result in an improvement in alignment, and a more reliable restoration of joint line.

Materials and Methods: Two consecutive series, each of 75 patients who had undergone TKR using either the old (Group A) or the new (Group B) instrumentation were included in the study. Antero-posterior and lateral preoperative and postoperative knee radiographs were assessed using the American knee society radiographic analysis for prosthesis postionoing by 2 independent observers. The Tibial and Femoral Component Angles in the coronal plane (cTCA and cFCA) and in the sagittal plane (sTCA and sFCA) were measured, as was the change in joint line height.

Conclusion: Our results suggest that use of the new instrumentation is associated with better restoration of joint line, and is more effective in preventing implantation of the tibial component in varus. These figures relating to a modern instrumentation system provide a yardstick against which computer assisted and robotic surgery can be judged. Long-term follow-up will be required to assess the clinical significance of these results.

Introduction: Progressive symptomatic tibiofemoral arthritis following PFJR is an important cause of failure. This study is designed to quantify radiologically the degree of tibiofemoral disease progression in patients who have undergone PFJR in our institution.

Patients and Methods: A prospective series of 102 consecutive Avon PFJRs in 78 patients with a minimum follow-up of five years was analysed.

Available AP weight bearing radiographs of the knee taken at 8 months and 5 years postoperatively were examined in a random order twice by each of two surgeons who were blinded to the patient details and length of follow up. The severity of arthritis was graded using the classifications of Ahlback and Altman, giving a measure of arthritis progression.

Results and Discussion: Arthritis was seen to progress in 8.5–17% of medial and 11–17% of lateral compartments after PFJR. Statistically significant progression was demonstrated using the Altman but not the less sensitive Ahlback scoring system, suggesting that the former should be used in scoring the tibiofemoral joint prior to PFJR. Of those patients who had a preoperative tibiofemoral Altman score of zero, 87% showed no radiological evidence of disease progression at minimum 5 year follow up, suggesting that these are the ideal candidates for PFJR.

Aim: The Low Contact Stress (LCS) Total Knee Replacements (TKR) is a well-established mobile bearing prosthesis with more than 25 year experience, while the Kinemax Plus is a well established fixed bearing prosthesis. We examined whether reproducing the joint line height to within 5 mm of the pre-operative joint line height had any impact on the clinical outcome in the two different types of Total Knee Replacements.

Method: 48 consecutive LCS knee replacements with a minimum of 2 years follow up had their pre and postoperative joint line (using Figgie’s method) and range of movement (ROM) measured. We used the Oxford Knee Score as a clinical outcome measurement tool.

A cohort group of 53 CR Kinemax plus TKR from the Bristol Knee group was matched for age and sex. They had the same parameters measured.

Results: Accurate joint line restoration was achieved significantly more frequently (P< 0.05) in the Kinemax group. Better post-operative ROM also occurred in the Kinemax group than the LCS, p = 0.03 and the former produced a bigger gain in ROM p < 0.01. However, no difference in the Oxford Knee Score existed between the two prostheses, p = 0.28.

Joint line: elevation K+ LCS

0–2 mm (16/48) = 33% (26/53) = 49% 2–5 mm (14/48) = 29% (14/53) = 26%> 5 mm (18/48) = 38% (12/53) = 25%

There was no significant difference in the ROM or Oxford Knee Score when the joint line was not elevated versus elevated for each prosthesis. However, there was suggestion that the ROM in LCS might be more sensitive to joint line changes, although this was not significant.

ROM

K+ LCS

Normal joint line 116° 105°

Elevated joint line 108° 101°

Conclusion: Accurate joint line restoration could not be shown to correlate with either improved ROM or Oxford knee score; probably because of the small mount of elevation encountered and the small study size. There was a significantly greater post-operative increase in ROM with the Kinemax Plus relative to the LCS, and a significantly closer restoration of the joint line with the Kinemax Plus, both with respect to the actual measurement and with respect to the proportion of cases in which the joint line was accurately reproduced. This is surprising since in most K+ cases additional distal femur had been resected to avoid a tight knee. While in the LCS group special efforts had been made to achieve accurate restoration of the joint level.

Aim: To describe a radiographic biomechanical classification of tibial plateau fractures which dictates treatment. To compare the intra- and interobserver reliability and reproducibility of this, the Chertsey (C1-3) classification, and the Schatzker (SK1-6) classification.

Method: This classification system has been used at this institution for 8 years by the orthopaedic trauma consultants and consists of C1 – valgus fractures, C2 – Varus fractures and C3 axial fractures. Our treatment regime is based on this classification and results presented in a sperate study. These consultants were excluded from the study on reliability and reproducibility. 2 Orthopaedic consultants, 2 orthopaedic registrars and 2 radiologists were selected randomly to classify 30 sets of AP and Lateral radiographs, of randomly selected patients treated in this institution with tibial plateau fractures, consisting of 9 SK1-3/C1, 8 SK4/C2 and 13 SK5,6/C3 fractures, and again with the same radiographs in a random order 1 month later. Radiographs of fractures treated conservatively were excluded. Statistical analysis included Kappa concordance according to Landis and Koch, and the Mann-Whitney U test.

Results: The Schatzker system was only moderately reliable (K=0.66), and the Chertsey classification system significantly more reliable (K=0.82) (p=0.03) with regards to interobserver reliability. Excellent reproducibility (intra-observer reliability) was seen amongst all observers. The consultant orthopaedic surgeons were significantly more reliable than the radiologists, but not the orthopaedic registrars. No particular fracture type in any classification proved to be significantly more difficult to classify.

Conclusion: We present a classification used in our institution based on plain radiographs, which depicts investigations and treatment. The Chertsey classification is significantly more reliable between observers than the Schatzker classification and is reproducible.

Introduction Unicompartmental Knee Replacement (UKR) has now become an accepted and widely used treatment for unicompartmental arthritis. Our unit has performed over 1000 UKRs in the past 22 years. The optimal mechanical design of the implant has yet to be determined.

Methods After gaining ethical approval a prospective randomised trial was commenced in 1999 to compare the 2–5 year results of a fixed bearing with a mobile bearing prosthesis. 104 knees in 91 patients underwent a UKR, the mean age of the group was 65 years and a mean weight of 80kg. 57 had a St Georg Sled fixed bearing prosthesis and 47 an unconstrained mobile bearing Oxford UKR. All were prospectively reviewed using the Oxford and Bristol Knee Scores.

Results All 104 knees have been reviewed at 2 years, with none lost to follow-up. 3 patients in the Oxford group suffered a dislocated meniscus and a further 4 required revision, as well as 3 in the St Georg Sled group. The overall function of the 2 groups was the same, but the Oxford mobile bearing group had significantly more persistent pain (p=0.013).

Conclusion The results in both groups were less satisfactory than previous series from this unit probably due to the efforts being made to use minimal incision. However the early complication rate was higher with the mobile bearing devise. This must be balanced against the possible better long-term survival.

Aims: To assay the intraoperative cerebral microemboli load during primary total knee arthroplasty(TKA) using transcranial Doppler ultrasound. A battery of ten neuropsychiatric tests were carried out pre and post operatively to examine the change in cognitive outcome. The relationship between emboli load and neuropsychiatric outcome was examined.

Methods: Patients undergoing primary TKA, with no history of stroke, TIA, ongoing CNS disease or alcoholism included. Pre (baseline) and post operative (6 weeks and 6 months) neuropsychiatric tests performed. Scores were recorded as “z change” scores compared with baseline. All operations were carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli load recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis.

Results: 50 TKA patients were studied. Cerebral microembolisation occurred in 63% of TKA patients. Mean microembolic load for TKA patients was 3.83 (range=0–57).

There was no significant change in neuropsychiatric outcome from baseline in these patients at 6 weeks or 6 months. Those patients that experienced cerebral microembolisation did not significantly differ in neuropsychiatric outcome from those that did not.

Conclusion: Intraoperative cerebral microembolisation occurs in almost half of patients during knee arthroplasty. Emboli loads are low and do not appear to cause early or late changes in neuropsychiatric outcome.

Introduction: Isolated patello-femoral arthritis occurs in up to 10% of patients suffering osteoarthritis of the knee. Reports of patello-femoral replacements have given indifferent results. We report our experience of 350 cases of the Avon Arthroplasty.

Method: In 1994 after experience with the Lubinus prosthesis which had a 50% failure rate at eight years, we defined the design criteria for a new prosthesis. Since September 1996, 350 knees have been treated with this design. Prospective review was undertaken and 150 knees have reached 2 years and 80 knees are at five years with 10 knees at eight years. The outcome was assessed using pain scores, Bartlett’s patella score and the Oxford knee score.

Results: The patients recovered function rapidly and 20 cases (6%) suffered early complications which resolved. The median pain score improved from 15/40 points to 38 at five years. The movement increased from 114 to 120 at five years. The Bartlett patella score improved from 11/30 points to 25 at five years. The Oxford knee score improved from 19/48 points to 40 points at five years.

The functional results are similar or better than those of a total knee replacement. Fourteen patients developed mal-alignment (4%) two of which required distal realignment. There have been no cases of deep infection, fracture, wear or loosening. Twenty seven knees (7%) developed evidence of disease progression, twenty two of which (6%) have required revision to a total knee replacement. Nineteen patients (5%) complained of some persistent anterior knee pain of uncertain cause.

Conclusions: Results to date show a large improvement in pain and function and this improved design has reduced the problems of mal-alignment and polythene wear. There is a low complication rate and an excellent range of movement. Disease progression remains a problem which is not predictable. This type of prosthesis offers an alternative to total knee replacement in this small group of patients with isolated patello-femoral disease with a low morbidity.

Purpose of the study: To develop a new treatment algorithm for patients with chronic anterior knee pain based on kinematic patella tracking MR imaging.

Methods and Results: Patients with anterior knee pain of more than one year duration and not responding to non-operative treatment, underwent kinematic MRI study. The provocative test was performed with the conventional MRI scanner and the patient extending the knee against resistance, the resistance provided by inflated beach ball. A retrospective analysis was done of first seventy patients, who had undergone this scanning technique.

On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking.

Conclusion: Kinematic MR Imaging is a useful investigation before considering operative treatment for patients with chronic anterior knee pain. Based on our study, we conclude that those patients with moderate lateral maltracking with a TTD< 18 mm should be offered lateral release and those with severe maltracking and TTD> 18mm should have a tibial tubercle transfer, in addition to lateral release.

Introduction: Proximal femoral fracture (PFF) is the leading cause of Trauma admission. Deep surgical wound infection occurs in approximately 3% of these patients. The purpose of this study was to assess the cost of deep infection to the patient, in terms of mortality and social consequences, and to the National Health Service, in terms of financial burden.

Methods: 61 consecutive patients (51 females, 10 males) treated for PFF, complicated with deep surgical wound infection over a seven-year period are presented. A control group consisting of 122 patients, without infection, were individually case matched (2:1) for factors that affect outcome after PFF (age, sex, ASA grade, fracture type, operation, and pre-fracture residence, social dependence, and mobility). Outcomes included length of admission (Trauma unit, rehabilitation bed, community hospital), number of operations, antibiotic administration and outpatient treatment, final destination, and mortality at one, three, and six months. A total cost of treatment was obtained from this data and supplied finance department figures.

Results: MRSA was responsible for 31 cases. Infected cases required an average of two wound debridements. 16 patients had a Girdlestones procedure of whom two were subsequently revised to total hip replacement. For all patients, the average Trauma unit admission was 58 days in the infected cases, with a further 40 days spent in rehabilitation or community beds, versus 16 days and 27 days respectively in the controls (p < 0.001). 34% of infected cases died before discharge versus 15% of controls (p = 0.004). For the patients surviving to discharge, the mean total hospital stay was 124 days for the infected cases versus 45 days in the controls (p < 0.001). A higher proportion of the survivors in the control group returned to their original residence compared to the infected survivors (p = 0.002). The mortality rates in the infected group were 15% at 1 month, 31% at 3 months, and 38% at six months, versus 9%, 20%, and 25% respectively in the control group (p = 0.36, 0.12, 0.12). The median cost of treatment per infected case was 23960 versus 7390 per control case.

Conclusions: Deep surgical wound infection after proximal femoral fracture is a devastating complication for both the patient and the NHS. It is associated with a higher in-patient mortality, and fewer survivors return to their pre-fracture residence. Hospital stay is greatly increased and survivors spend 4 months on average in hospital. Additional costs are huge and are incurred at all levels. The extra financial cost of treating a single infected case would fund the treatment of two non-infected cases. These costs should be considered when allocating funds and beds to Trauma services, in addition to ensuring measures known to minimise infection rates are in place.

Introduction. There has been a recent major increase in the use of unicompartmental knee replacement (UKR) but few studies exist comparing its long term efficiency with total knee replacement (TKR)

Method. Ethical approval was obtained.

Between 1989 and 1992 a randomised prospective study was undertaken in which 102 cases adjudged suitable for UKR were allocated to receive either a St Georg Sled UKR or a Kinematic Modular TKR. Both cohorts had a median age of 68 and a similar sex distribution and preoperative knee score. Regular follow up has been maintained. As reported the early results favoured UKR. All cases have now been assessed after a minimum of 10 years using modified WOMAC, Oxford and Bristol Knee Scores (BKS) as well as radiographs.

Results. 28 cases had died with their knees known to be intact, 2 cases were untraceable. 33 knees in each group were reviewed. 3 in each group had been revised, no impending failures were identified on the radiographs.

At 10 years the UKR group had better Oxford and WOMAC scores as well as significantly more excellent results (19:14) and fewer fair and poor results on the BKS. Both groups averaged over 105′ of flexion but 61% of the UKR and only 15% of the TKR group had 120′ or more of flexion.

Conclusion. The faster rehabilitation and better early results with UKR are maintained for 10 years with few failures occurring. The average BKS of the UKR group only fell from 91 to 88 between 5 and 10 years suggesting minimal evidence of functional deterioration in either the prosthesis or the remainder of the joint.

Introduction and Aims: Single compartmental replacement procedures are increasingly preferred over total knee replacement (TKR) for single compartment osteoarthritis of the knee joint. Theoretically, reduced disruption of the native joint should produce more normal kinematics. This study aimed to describe and compare the sagittal plane kinematics of four different, commonly used devices.

Method: Four groups of patients who had undergone successful single compartment replacement at least two years previously were recruited. Fifteen following Oxford medial UKA, 12 following medial St Georg Sled UKA, five following Oxford lateral UKA, and 12 following Avon PFJ replacement. Patients performed flexion/extension against gravity, and a step-up during video fluoroscopy. The Patellar Tendon Angle (PTA), the angle between the long axis of the tibia and the patella tendon, was obtained as a function of knee flexion. This relationship provides indication of sagittal movement between femur and tibia through range and has been validated as a reliable measure of joint kinematics.

Results: The kinematic profile for each group was compared to that of the profile for 12 normal and 30 TKR (AGC) knees. All three tibiofemoral devices produced knee kinematics similar to the normal knee. The PTA was found to have a linear relationship to flexion angle, decreasing with increasing knee flexion angle. No such linear relationship exists for the TKR joint, which display abnormal kinematics. The PF device also reflected similar trends to that for normal knees except that the PTA was moderately increased throughout the entire range of flexion (three degrees).

Conclusion: In contrast to TKR, all single compartmental knee replacements provided kinematics similar to the normal joint. The kinematic pattern of the PFJ replacement may be of most interest as the observed increase in PTA through range could influence patello-femoral contact forces

Introduction: Uni-compartmental Knee Replacement (UKR) has now become an accepted and widely used treatment for uni-compartmental arthritis. Our unit has performed over 1000 UKRs in the past 22 years. The optimal mechanical design of the implant has yet to be determined.

Method: A prospective trial was commenced in 1999 to compare the short-term results of a fixed bearing with a mobile bearing prosthesis. One hundred and three knees in 95 patients underwent a UKR. Fifty-three had a St Georg Sled fixed bearing prosthesis and 50 had unconstrained mobile bearing Oxford UKR. All were prospectively reviewed using the Oxford and Bristol Knee Scores.

Results: Eighty-four knees have been reviewed at two years with one lost to follow-up. One fixed (2%) and six mobile (12%) bearing knees had been revised. Three fixed bearing and eight mobile bearing knees were dissatisfied because of stiffness or persistent pain and seven mobile bearing knees had undergone further minor procedures, usually for dislocation. At two years, the Bristol and Oxford knee scores for fixed bearing were better than the mobile bearing knees at 90:83 /100 and 38:33 /48 respectively.

Conclusion: There were more early complications in the mobile bearing UKR group, but the functional results were slightly better than in the fixed bearing knees.

Introduction and Aims: There has recently been an increase in the use of uni-compartmental knee replacement (UKR), but there are few studies comparing its long-term efficacy and survival with total knee replacement (TKR). We reported the five-year results of a randomised trial which showed that uni-compartmental replacement had a faster rehabilitation and better functional results than total replacement. We now report the 10-year results.

Method: After obtaining ethical approval, between 1989 and 1992, 102 cases judged suitable for UKR were randomly allocated to receive either a St Georg Sled UKR or a Kinematic Modular TKR. Both cohorts had a median age of 68 and a similar sex distribution and pre-operative knee scores. Regular follow-up has been maintained. All cases have now been assessed after a minimum of 10 years using modified the WOMAC, Pain, Oxford and Bristol Knee (BSK) scoring systems as well as radiographs.

Results: At 10 years, 29 cases had died with their knees known to be intact, two totals cases were untraceable. Thirty-two uni`s, and 34 totals were available for review. Three uni`s (6%) and two totals (4%) had been revised; there was one impending total failure on the radiographs.

The UKR group had better scores with Oxford: 38 v 34 /48 and WOMAC: 17 v 21 /60 and more excellent results (19 v 14) and fewer fair and poor results on the BKS (4 v 6). The range of movement improved in UKA`s from 107 degrees to 117 degrees, whereas the range decreased in TRK`s from 107 degrees to 104 degrees. Sixty-one percent of the UKR and only 16% of the TKR group had more than 120 degrees of flexion.

Conclusion: The St Georg Uni-compartmental arthroplasty continues to function well at 10 years, with better functional scores and a better range of movement than the Kinematic Total arthroplasty. There were similar failures in both groups.

Introduction: Isolated patello-femoral arthritis occurs in up to 10% of patients suffering osteoarthritis of the knee. Reports of patello-femoral replacements have given indifferent results so we wish to report our experience of 326 cases using two different protheses.

Method: In 1989 we started a prospective series of the Lubinus prosthesis. The results of 76 cases at eight years showed a 50% failure rate. The main reasons for failure were malalignment, wear and disease progression. The Avon patello-femoral arthroplasty was designed to solve some of these problems.

Since September 1996, 250 knees have been treated. Prospective review was undertaken and 120 knees have reached two years and 40 are at five years. The outcome was assessed using pain scores, Bartlett’s patella score and the Oxford knee score.

Results: The median pain score improved from 15/40 points to 35 at five years. The movement increased from 114 to 120 degrees at five years. The Bartlett patella score improved from 10/30 points to 26 at five years. The Oxford knee score improved from 19/48 points to 40 points at five years.

The functional results are similar to those of a total knee replacement. Two patients developed malalignment (1%) one of which required distal soft tissue realignment. There have been no cases of deep infection, fracture, wear or loosening. Sixteen knees (6%) developed evidence of disease progression, 14 of which (6%) have required revision to a total knee replacement.

Conclusions: Results to date suggest that this improved design has reduced the problems of malalignment and early wear. There is a low complication rate and an excellent range of movement. Disease progression remains a problem that is not predictable. This type of prosthesis offers an alternative to total knee replacement in this small group of patients with isolated patello-femoral disease with a lower morbidity.

Introduction and Aims: Our experience with over 200 cases of Avon patellofemoral replacement (PFR) in the elderly with severe arthritis has been satisfactory, so we have extended the indications to younger patients with severe symptoms and various pathologies.

Method: Sixty-six knees in 53 patients (10M: 46F) under the age of 55 years (average 47 years) have been treated with an AVON PFR for the following conditions:

PATHOLOGY NUMBER of Knees

Isolated lateral facet OA 34

Failed realignment 12

Persistent subluxation/dislocation 5

Trochlear dysplasia 5

Pure chondral disease 3

Failed carbon fibre implant 3

Post-patellectomy instability 3

Post-traumatic pain 1

All patients were recorded prospectively and have been regularly reviewed using the modified Oxford, Bartlett & Bristol Knee scoring systems. The mean follow-up of the group is 24 months.

Results: No patient has been lost to follow-up, all knee scores improved substantially.

Most of the patients retained their range of flexion and the mean range of movement increased from 112 to 122 degrees. Patients with persistent subluxation were the most dramatically improved. There have been no cases of deep infection, loosening or wear.

Conclusion: Avon PFR provides a reliable short-term solution to some of the more difficult and disabling problems of the patello-femoral joint as long as demonstrable pathology is present.

Introduction and Aims: Kneeling is an important function of the knee joint but little information is available on ability to kneel after different types of knee arthroplasty. We aimed to assess patients’ kneeling ability pre- and post-operatively after uni-compartmental, patellofemoral and total knee arthroplasty (UKR, PFR, TKR) and to objectively examine: kneeling ability, factors that affect it and whether this ability differed from the patient’s perception.

Method: In 253 knee arthroplasty cases, we prospectively analysed the ability to kneel pre-operatively, and post-operatively at one and two years using the relevant section of the Oxford Knee Score questionnaire. One hundred and twenty-two post-operative patients (38 TKR, 53 UKR, 31 PFR) were then examined to assess their actual kneeling ability.

Results: Patients’ perception of their kneeling ability prior to surgery was poor in all three groups (mean score 0.7 out of 4) and improved in all groups after surgery (mean score at two years 1.46 out of 4). Perceived kneeling ability was best in UKR and worst in PFR (P< 0.001). Perceived kneeling ability improved most in the first year post-operatively, but continued to improve between one and two years although the final kneeling function was still not good. When examined, only 37% of patients thought they could kneel, whereas 81% were actually able to kneel (P< 0.001). Ability to kneel was significantly better than perceived ability for all prosthesis types (P< 0.001). Kneeling ability was better in men and associated with an increased range of movement (P< 0.001).

Conclusion: Kneeling ability is poor prior to knee arthroplasty and improves up to two years post-operatively, though it is still perceived to be poor, but can be improved with rehabilitation. UKR gave better kneeling ability than PFR or TKR. Patient-centred questionnaires do not accurately document kneeling ability after knee arthroplasty.

Purpose This study was carried out to compare the alteration in skin sensation following midline, medial and short medial incisions for knee replacement.

Method 88 patients with 102 knees were examined for altered skin sensation over the front of the knee, all were at least 18 months from their knee replacement. Twenty-one knees had a medial incision, 38 a midline incision and 43 a short medial incision for UKR.

A scale of −2 to +2 was used to measure different degrees of skin hypo or hyperaesthia. A purpose-designed grid, designed to fit different knee sizes, was used to record sensations. A computer programme was created to record all patients’ data including the length and shape of the incision in relation to anatomical landmarks.

A parallel histological study was carried out on 12 skin specimens taken from the 2 standard incisions. The specimens were prepared and stained for nerve endings. The number of nerve endings in each incision was calculated.

Results The average length for the medial incision was 17 cm with an average post-operative time of 3.37 yrs and skin numbness of 87.78 cm square.

The midline incision average length was 17.85 cm with an average post-operative time of 4.7 yrs and a numb area of 73.7 cm square.

The short medial incision used for UKR averaged to be 9 cm in length with an average post operative time of 3.9 yrs and an area of numbness of 48.1 cm square.

Histologically less cutaneous nerve endings were seen in specimens from midline incisions than medial incisions.

Discussion The midline line incision seems to produce less dermal parasthesia than the medial incision, this probably relates to both the wound position and the density of nerve endings. The length of the incision correlated with the area of numbness when comparing the short and long medial incisions.

Purpose: To assess the outcome of customised hinged knee replacements when used to salvage catastrophically failed knee replacements in elderly patients.

Methods: Since 1993, 30 of the 280 (10.7%) revision knee replacements at the Avon Orthopaedic Centre, Bristol have used Endo customised hinged knee pros-theses (21 rotating, 9 fixed) for salvage of limb threatening situations in elderly patients. All were prospectively recorded and regularly reviewed. The average age was 75 years with a predominance of females. Surgical indications were 22 periprosthetic fractures (with or without aseptic loosening), 5 massive aseptic osteolyses, and 3 deep infections.

Results: The mean length of postoperative hospital stay was just 14.6 days and all patients were discharged walking with aids. At follow up (mean 3.0 years, range 0.5–9.3 years) 9 patients had died with their prostheses in situ and functioning. 2 had undergone amputation for recurrent sepsis and 2 had received further surgery for septic problems. 2 patients required further surgery for prosthetic disarticulation and one patient had successful on table vascular repair. 25 patients had mid or long term follow up. Their mean American Knee Scores (AKS) were 69.8 for knee and 35.6 for function (maximum 100), with a mean total knee flexion of 83 degrees. Mean Oxford knee scores (OKS) and WOMAC scores (both scored between 12 and 60 with low score indicating less difficulties) were 34.0 and 30.5 respectively.

Conclusions: Customised hinge revision knee replacements gave extremely rapid rehabilitation and hospital discharge which justified the high prosthetic cost. Complications were high but at mid and long-term review, no prostheses had failed from an aseptic cause and most of the knees of this challenging group were providing both stability and flex

Purpose of the study: To develop a new treatment algorithm for patients with chronic anterior knee pain based on kinematic patella tracking MR imaging.

Methods and Results: Patients with anterior knee pain of more than one year duration and not responding to non-operative treatment, underwent kinematic MRI study. The provocative test was performed with the conventional MRI scanner and the patient extending the knee against resistance, the resistance provided by inflated beach ball. A retrospective analysis was done of first seventy patients, who had undergone this scanning technique.

On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking.

Conclusion: Kinematic MR Imaging is a useful investigation before considering operative treatment for patients with chronic anterior knee pain. Based on our study, we conclude that those patients with moderate lateral maltracking with a TTD< 18 mm should be offered lateral release and those with severe maltracking and TTD> 18mm should have a tibial tubercle transfer, in addition to lateral release.

Following total hip arthroplasty (THA) and total knee arthroplasty (TKR) only the ‘visible’ measured blood loss is usually known. This underestimates the ‘true’ total loss, as some loss is ‘hidden’. Correct management of blood loss should take hidden loss into account.

We studied 101 THAs and 101 TKAs (with re-infusion of drained blood). Following THA, the mean total loss was 1510 ml and the hidden loss 471 ml (26%). Following TKA, the mean total loss was 1498 ml. The hidden loss was 765 ml (49%). Obesity made no difference with either operation.

THA involves a small hidden loss, the total loss being 1.3 times that measured. However, following TKA, there may be substantial hidden blood loss due to bleeding into the tissues and residual blood in the joint. The true total loss can be determined by doubling the measured loss.

Aim: The aim of this study was to evaluate the functional results and ease of performing revision surgery after a primary unicompartmental arthroplasty versus primary total knee arthroplasty.

Method: 114 revision TKRs had data collected prospectively as part of our unit’s Knee Database. 45 were revisions of UKR’s and 79 revisions of TKR’s. This data included Bristol Knee Scores (BKS), reason for revision, use of implant augments and bone graft. Measurements were also made of the ability to restore joint-line after revision.

Results: In both groups there was a significant improvement in BKS post-operatively. In the UKR group the commonest reason for revision was progression of disease, while in the TKR group it was aseptic loosening. Bone graft was required in significantly fewer UKR cases (20% vs 40%, P< 0.05). Distal femoral augments were used in 45% of the TKR revisions but in none of the revisions from UKR. The joint line was elevated in a significantly higher proportion of revision from TKR cases versus revision from UKR cases (P< 0.001). Revisions from UKR had higher Total BKS and Functional BKS score than revisions from TKR.

Conclusions: Revision TKR after a primary UKR requires less bone graft, fewer augments, restores the joint line more frequently and gives improved functional results over revisions after primary TKR.

Purpose A new design of patello-femoral arthroplasty has been used to treat patients under 55 years suffering severe symptoms from chondral and early arthritic disease of the patello-femoral joint.

Materials and Methods and Results Fifty-two patello-femoral arthroplasties were performed in 45 patients under the age of fifty-five years when other treatments had failed. The average age was 48 years (range 36–54 years). Thirty-seven cases had undergone previous surgery for a variety of conditions, and the causes of the disorders were analysed. Results were assessed using pain scores and Bartlett’s and Oxford functional scores. 35 cases were reviewed at 8 months and 22 cases at two years. The median pain score improved from 10/40 points to 35 at two years. The Bartlett score increased from 10/30 points to 27 and the Oxford score from 19/48 points to 35 at two years. The range of movement increased from 114° to 121°. There have been no cases of deep infection, loosening, wear or instability. Disease progression, a potential risk has occurred in one case.

Conclusions This prosthesis offers a solution in younger patients with disabling symptoms of isolated early patello-femoral disease who have not responded to conservative surgical management.

The study was designed to compare the clinical performance of an Alumina ceramic acetabular bearing to that of a polyethylene bearing in a cementless hip couple.

The study group consisted of 15 surgeons who performed 308 total hip replacements (297 patients) between January 29, 1998 and February 1, 2000. All patients received a porous coated cementless titanium stem with an Alumina ceramic 28 mm or 32 mm head. Patients were randomized to receive a porous titanium acetabular shell with either a polyethylene or Alumina cup liner. There were 164 Alumina cups and 144 polyethylene cups. The mean age was 57.3 years and consisted of 50% males and 50% females. The preoperative diagnoses were: osteoarthritis 69.8%, avascular necrosis 19.5 %, post traumatic arthritis 2.9 %, inflammatory arthritis 3.9% and other 3.9%. The mean follow up was 12 months. The longest follow up was 38 months.

The Harris Hip Score was good and excellent in 86% of the control patients and 87% of the study patients. There has been 100% follow up and survivorship.

There were two reoperations for recurrent dislocations in each group. There were no Alumina component fractures, no progressive radiolucencies and no evidence of rapid wear.

In the short term follow-up between 12 and 38 months, there do not appear to be any differences between the patients with a bearing couple consisting of Alumina on plastic with those consisting of Alumina on Alumina. There have been no catastrophic failures of the ceramic components. The Alumina/Alumina bearing couple for total hip arthroplasty appears to be an excellent alternative bearing, providing the advantage of improved long term wear and a reduced incidence of polyethylene induced osteolysis.

Aim: To assess the functional results of revision TKR with the PFC/TC3 system, and to correlate this with the reasons for revision and restoration of joint height. Method: 153 patients underwent revision TKR using the PFC/TC3 system. Data was prospectively collected (using the Bristol Knee Score) pre-operatively and at a mean of 4.2 years post-revision. 43 revisions were for infection and 81 revisions were for aseptic loosening. Measurements of the joint height were made pre and post-operatively using FiggieÔs method and were divided into 3 groups: lower by more than 5mm, restored and elevated more than 5mm. Use of distal augments and polyethylene thickness were recorded. Results: The mean pre-op function score was 12 and post-operatively was 19 for the infection group and 20 for the aseptic loosening group. Revision after initial UKR gave a mean score of 21, while revision after TKR gave a mean score of 18 (max 27). Knees in which the joint line was elevated by more than 5 mm had a mean score of 17 while those where the joint line was restored had a mean score of 19. Recent increasing use of distal augments improved the joint line and results. Conclusion: revision using the PFC/TC3 system produced acceptable medium term functional results and good survival. Better restoration of joint line and functional results were achieved by distal femoral rather than proximal tibial augmentation.

Aims: To investigate whether normal statistical ßuctuation in the incidence of early complications of primary Knee Arthroplasty (TKA) follows the laws of statistical probability and can thus be amenable to analysis by standard Statistical Quality Control (SQC) methods. The þnal objective is to apply such techniques to distinguish random ßuctuation from real (undetected by traditional p value statistical methods) increase in the incidence of early complications in primary joint Arthroplasty. Methods: We employed statistical quality control charts (X-bar, p, c, u and np) to analyse postoperative complications and length of stay in 1,196 consecutive primary TKAs performed over a 20-quarter time period (October 1995 to September 2000). For all analyses (Minitab 12.1 software) the standard practice of employing ± 3 standard deviation upper and lower control limits and generally accepted criteria for determining the presence or absence of statistical control were used. Results: Deep infection, major thromboembolic incident, total number of complications per case and total number of complicated cases appeared to be in stable statistical control and followed the laws of statistical ßuctuation throughout the entire study period. However, patella mal-tracking, persistent knee stiffness, postoperative length of stay and total number of postoperative complications showed an (undetected by conventional postoperative audit methods) lack of control at various time periods with subsequent return to the statistically-controlled range. Conclusions: SQC methods may be employed in the audit of postoperative events in TKA and can be a valuable tool in continuous assessment of the statistical variability of postoperative complications, with the aim of reducing the variability and improving clinical outcome Arthritic knee imaging

Aims: To compare the intraoperative cerebral microemboli load between primary total hip (THA) and knee arthroplsty (TKA) using transcranial Doppler ultrasound and to investigate whether a patent foramen ovale influences cerebral embolic load in general. The timing of the microemboli will be related to certain surgical activities to determine if a specific relationship exists. Methods: Patients undergoing primary TKA or THA, with no history of stroke, TIA, ongoing CNS disease or alcoholism included. All operations carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli load recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis. Patent foramen ovale detection performed using bolus intravenous injection of agitated saline followed by valsalva manoeuvre technique and TCD. Timing of specific surgical steps recorded for each operation and emboli load calculated for that period. Results: 20 THA and 20 TKA patients were studied. Cerebral microembolisation occurred in 50% of THA and 40% of TKA patients. Total microembolic load for THA patients was 137 (range=0–83) and 50 (range=0–21) for TKA patients. Prevalence of PFO in the THA group was 35%, and 20% in the TKA group. 57.1% of PFO positive THA patients and 75% of PFO positive TKA patients displayed microemboli. Insertion of the femoral component in THA and release of the tourniquet in TKA were associated with higher cerebral microemboli load. Conclusion: Intraoperative cerebral microembolisation occurs in almost half of patients during hip and knee arthroplasty. Patients who have a PFO appear more likely to be associated with cerebral embolisation. Specific surgical activities are associated with larger embolic loads.

Introduction: Lateral uni-compartmental knee replacement (UKR) is seldom indicated and remains controversial. It has been considered a technically challenging operation with variable success. Aim: The aim of this paper is to assess the results of unicompartmental knee replacement using a þxed noncongruous prosthesis. Methods: Eighty-eight knees in 79 patients with lateral unicompartmental osteoarthritis treated with a þxed bearing, non-congruous, fully unconstrained prosthesis. (St Georg Sled UKR) over a period of 21 years by different consultants and there trainees. Surgical approach and rehabilitation protocol varied over this period but there was no change in the surgical indications. Results: At a mean follow up of 9 years (range 2 to 21 years). Fifteen knees had revision surgery (9 for progression of arthritis and 6 for component loosening, 4 for implant breakage and 4 for more than one reason). Six patients complained of moderate or severe pain at þnal follow up. Only þve knees were lost to follow up in the 21-year period. Survivorship analysis was performed on the group using revision for any cause as the end point. At ten years the cumulative survival rate was 83% and at 15 years, when ten knees were still at risk, the cumulative survival rate was 74%. Conclusion: Based on our clinical results and survival rate the St Georg Sled UKR can be considered a suitable treatment for isolated lateral compartment osteoarthritis.

The diagnosis and subsequent treatment of patients with “Anterior Knee Pain” remains a challenge and an enigma at times.

The 4 main parameters, which need to be assessed, are:

Bony anatomy of the PFJ

While plain radiographs, CT scans and static MRI sans and arthroscopic assessments highlight some of the parameters none of them are comprehensive. The type of MRI scanning used in this study assesses all 4 parameters. The equipment required for resisted quadriceps contraction is inexpensive and readily available.

Material and Methods: 70 patients had dynamic MRI scans done over a period of 2 years. The study consisted of 3 parts:

Radiological diagnosis and grading of subluxation if present.

Conclusion: The Tibial Tubercle to Trochlear Groove Distance” (TTD) appears to be the single most significant parameter determining patellar tracking. Objective radiological assessment is possible under physiological loading, to differentiate tilt, subluxation and chondromalacia. We have proposed an algorithm for the surgical and non-surgical treatment of anterior knee pain. The pain scores did not show a significant correlation with the grading of subluxation.

Aims: To quantify the intraoperative cerebral microemboli load during primary total hip arthroplasty (THA) using transcranial Doppler ultrasound and to investigate whether a patent foramen ovale influences cerebral embolic load in general. The timing of the microemboli will be related to certain surgical activities to determine if a specific relationship exists.

Methods: Patients undergoing primary THA, with no history of stroke, TIA, ongoing CNS disease or alcoholism were included. All operations were carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli load was recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis. Patent foramen ovale detection was performed using bolus intravenous injection of agitated saline followed by valsalva manoeuvre technique and TCD. Timing of specific surgical steps was recorded for each operation and emboli load calculated for that period.

Results: 25 THA patients were studied (18 females, 7 males) 16 right and 9 left THA’s were performed. Cerebral microembolisation occurred in 10 patients (40%). Mean microembolic load was 5.52 per patient (range = 0–83). PFO was detected in 8 patients (32%). 37.5% of PFO positive patients displayed cerebral microemboli. However, 41.1% of PFO negative patients also displayed microemboli intraoperatively.

Insertion of the femoral component was associated with generating a larger microembolic load than the other phases of the operation.

Conclusion: Intraoperative cerebral microembolisation occurs in a significant proportion of patients during total hip arthroplasty. The presence of a patent foramen ovale does not appear to influence the incidence microemboli intraoperatively. Specific surgical activities are associated with generating greater embolic loads. These questions will be comprehensively assessed in the larger study currently underway..

Between June 1986 and 1993, 208 Protek CLS total hip replacements were inserted in 174 patients. These have been reviewed clinically and radiologically by independent observers at 3 yearly intervals.

One hundred and sixty six hips in 137 patients were available for review 9 to 15.5 years from insertion (mean just over 10.5 years). There has been no significant clinical or radiological change when compared to reviews three and six years ago with regard to the Harris Hip Score and the pain and function components of this. There has also been no change in subsidence, heterotopic ossification or lucencies. There has been no significant difference in results between males or females, nor between other factors such as pre-operative diagnosis, the use of metal or ceramic heads, age at time of operation or length of follow up. The failure rate remains low, less than 4%, i.e. survival rate greater than 96%. The reasons for failure in general do not relate to the fixation of either the acetabular or femoral components.

The results of this long-term follow up of a large group of relatively young patients at time of insertion of arthroplasty remain very satisfactory.

Traditionally, immobilisation following achilles tendon rupture has been for 10 to 12 weeks.

We have previously published a series of 71 consecutive repairs with no re-ruptures, using a lateral surgical approach. The latter part of this cohort were immobilised for six weeks instead of 12, with early weight bearing. The lack of any re-ruptures encouraged us to pursue the accelerated rehabilitation.

This study documents a further 34 cases followed prospectively for 6–24 months (mean 15.9 months). All were repaired with a single Kessler-type suture using loop PDS, through a lateral approach. Patients were partial weight-bearing immediately in an Aircast boot with three cork heel wedges. At two-weekly intervals the wedges were reduced, and the boot abandoned after six weeks.

There have been no re-ruptures. Thirty of the 34 patients returned to pre-injury activity levels. All patients were satisfied or very satisfied with the immobilisation device and the accelerated rehabilitation regime. Cost savings were also made through use of a single removable orthosis rather than sequential casts.

We advocate this regimen of careful operative achilles tendon repair and accelerated weight bearing rehabilitation with a removable orthosis.

The purpose of the study was to review and present a series of early failures of the Miller Galante unicom-partmental knee replacement (UKR). Following several early failures all Miller Galante UKR’s inserted by the author (60 patients, 72 knees) were recalled for clinical and radiological review including assessment using the American Knee Society Score and the Oxford Knee Score. All knees with effusions were aspirated and specimens sent for histological analysis.

There were 22 females and 38 males with a mean age of 67 years. The mean follow up was 3.4 years. Six failures were noted with follow up from 10 months to 4 years. These 6 cases will be discussed in more detail including operative findings at revision and possible reasons for failure.

Early failure of this arthroplasty is unacceptable and caution should be exercised if contemplating using this implant unless more definite causative factors are identified.

Traditionally, immobilisation following Achilles tendon rupture has been for 10 to 12 weeks.

We have previously published a series of 71 consecutive repairs with no re-ruptures, using a lateral surgical approach. The latter part of this cohort were immobilised for six weeks instead of 12, with early weight bearing. The lack of any re-ruptures encouraged us to persue the accelerated rehabilitation.

This study documents a further 34 cases followed prospectively for 6–24 months (mean 15.9 months). All were repaired with a single Kessler-type suture using loop PDS, through a lateral approach. Patients were partial weight-bearing immediately in an Aircast boot with three cork heel wedges. At two-weekly intervals the wedges were reduced, and the boot abandoned after six weeks.

There have been no re-ruptures. Thirty of the 34 patients returned to pre-injury activity levels. All patients were satisfied or very satisfied with the immobilisation device and the accelerated rehabilitation regime. Costs savings were also made through use of a single removable orthosis rather than sequential casts.

We advocate this regimen of careful operative achilles tendon repair and accelerated weight bearing rehabilitation with a removable orthosis.

Isolated patello-femoral arthritis occurs in up to 10% of patients suffering osteoarthritis of the knee. Previous reports of several different patello-femoral designs have given indifferent results. The Lubinus prosthesis has a reported 50% failure rate at eight years in a study of 76 cases. The main reasons for failure were mal-alignment, wear, impingement and disease progression. The Avon patello-femoral arthroplasty was designed to solve some of these problems.

The first cases were implanted in September 1996 and entered into a prospective review. The outcome was assessed using pain scores, Bartlett’s patella score and the Oxford knee score. To date 207 knees have been treated and 95 knees have reviewed at two to five years. The median pain score improved from 15/40 points to 35 at five years. The movement increased from 114° to 120° at five years. The Bartlett patella score improved from 10/30 points to 26 at five years. The Oxford knee score improved from 19/48 points to 40 points at five years. Two patients developed mal-alignment (1%) one of which required distal soft tissue realignment. There have been no cases of deep infection, fracture, wear or loosening. Fifteen knees (7%) developed evidence of disease progression, twelve of which (6%) have required revision to a total knee replacement. The functional results are similar to those of a total knee replacement.

Results to date suggest that this improved design has all but eliminated the previous problems of mal-alignment and early wear. The functional results are as good as or better than those of a total knee replacement. There is a low complication rate and an excellent range of movement. Disease progression remains a potential problem. This type of prosthesis offers a reasonable alternative to total knee replacement in this small group of patients with isolated, early patello-femoral disease.

The aim of this study was to examine causes of the failed knee arthroplasty.

Since 1980 the Bristol Knee Replacement Registry has prospectively recorded data on 3024 patients. Complete original and 5 year follow up data was available on 999 knees.

The surgery was judged a failure if there was no improvement in the American Knee Society score at 5 years or if there had been a revision within that time.

The prosthesis used was Kinematic in 471 knees, the Medial Unicompartmental Sled in 258 knees, the Kinemax Plus in 134 knees and a variety of other designs.

At 5 years, 79 (7. 9%) either showed no improvement in the American Knee Society score or had been revised. The failure rate was 7% for the Kinematic, 7% for the medial Sled and 5% for the Kinemax Plus. 20% of the less frequently used designs failed.

Five (0. 5%) knee replacements failed because of infection. 22 knees (2. 2%) had significant comorbidity that precluded a satisfactory functional outcome. For 7 knees (0. 7%), the patient exhibited patterns of abnormal illness behaviour that were thought to explain the poor outcome. A further 27 knees (2. 7%) failed because of technical errors either at the time of surgery (13 cases, 1. 3%), or in selecting a prosthesis which failed prematurely (14 cases 1. 4%). No cause for failure could be identified in 12 cases (1. 2%).

The high failure rate amongst infrequently used prosthesis emphasises the need to use established designs. No cause for failure could be identified in 12 cases and 5 were due to infection; such cases are hard to avoid. This study shows the importance of assessing both the overall physical and psychological state of the patient if disappointing results are to be avoided. The most frequent cause of an unsatisfactory outcome was a technical one, which should be avoidable.

Isolated patellofemoral arthritis occurs in up to 10% of patients suffering osteoarthritis of the knee. Previous reports of several different patellofemoral designs have given indifferent results. The Lubinus prosthesis has been shown to have a 50% failure rate at eight years in a study of 76 cases. The main reasons for failure were mal-alignment, wear, impingement and disease progression. As a result of these studies, a new prosthesis was designed to solve some of these problems.

The Avon patellofemoral arthroplasty was first implanted in September 1996. The cases have been entered into a prospective review with evaluations at eight months, two years and five years. The outcome was assessed using pain scores, Bartlett’s patella score and the Oxford knee score. To date, 186 knees have been treated; over 100 knees have been reviewed at two years and 20 knees at five years. The main pain score improved from a pre-operative level of 13.5 points out of 40 to 33.5 points at two years and 36 at five years. The mean pre-operative movement was 109° and this increased to 120° at five years. The Bartlett patella score improved from a pre-operative level of 10.5 points out of 30 pre-operatively to 23 points at two years and 25 at five years. The Oxford knee score was 20 points out of 48 pre-operatively and this improved to 35 points at two years and 40 points at five years. One patient developed subluxation, which required distal soft tissue realignment. No other patient has developed problems with alignment or wear. Ten knees have developed evidence of disease progression usually in the medial compartment of which six have required revision to a total knee replacement.

The results to date suggest that this improved design has all but eliminated the previous problems of malalignment and early wear. The functional results are as good or better than those of a total knee replacement. There is a low complication rate and an excellent range of movement. Disease progression remains a potential problem. This type of prosthesis offers a reasonable alternative to total knee replacement in this small group of patients with isolated, early patellofemoral disease.

The Bristol Knee Replacement Registry was established in the 1970’s and contains prospectively recorded data on 3024 patients. The present study examines the group of 812 patients for whom complete pre-operative and five year post-operative data is available in order to relate their eventual health status to the pre-operative demographic data and to disease severity. The group comprised 593 women and 219 men who had undergone either Kinematic, Total or Sled unicompartmental knee replacement.

Pre-operatively, the average American Knee Society Score (AKSS) was 89 with the elderly, rheumatoid patients and women having significantly lower scores.

Five years later the average AKSS had risen to 161 with patients of all ages, (including the over 80’s) gaining considerably. However, the rheumatoid patients remained more disabled as did women who had a final AKSS of 157 as opposed to 171 for the men (p< 0.01). In addition, a statistically significant finding was that those with the lowest pre-operative scores also had the lowest 5 year scores - they never catch up.

173 patients underwent bilateral knee replacement at separate times. Their pre-operative AKSS was significantly higher at the time of the second knee replacement (90) than the first (82) p< 0.01.

We conclude that since patients present earlier for their second TKR and those with most disability fail to catch up the procedure should be performed earlier in the natural history of the disease, especially in women.

The aim of this study was to report our experience of patellofemoral arthroplasty in isolated osteoarthrosis.

Material and Methods: The Lubinus Patellofemoral Arthroplasty was performed between 1989 and 1995 in 76 knees. The Avon Patella Femoral Arthroplasty was used from 1996 to 2001 in 187 knees. The average age of the patients was 65.5 years (range 36–87) with a male to female ratio of 1: 5. All the patients have been prospectively reviewed with standard radiographs, the Bristol Knee Score, and more recently Bartlett and Oxford scores.

Results: Patients with the Lubinus prosthesis were followed for an average of 7.4 years (range 5–10 years). Eleven patients (14 knees) have died and the remaining 62 knees have a 100% follow-up. The cumulative revision rate was 28% (21 out of 76). Survivorship at 8 years was 65% (Cl 49 to 77) for revision and 48% (Cl 36 to 59) for revision plus moderate pain. The two main complications were Maltracking 32% and progressive tibio-femoral arthritis in 9%.

The Avon Arthroplasty with improved design features for better tracking and congruity was introduced in 1996 and 187 have now been inserted in 147 patients. One hundred and nine knees have been followed for 8 months and 82 have completed the 2 year follow-up. Two patients have undergone revision to a TKR 97.5% (survivorship 2 out of 82). Three patients have had a unicompartmental arthroplasty added for disease progression. There have been no cases of patella maltracking or subliaxation.

Four year survivorship for moderate pain and revision is 96% (79 out of 82). Functional scores compared favourably with parallel series of total knee replacements.

Conclusion: The medium-term results of the Lubinus Patello Femoral Arthroplasty are unsatisfactory. We suggest the use of this prosthesis should be discontinued. The Avon Arthroplasty has improved results in the short-term.

The purpose of this study was to determine the rate of polyethylene wear in a fixed bearing knee replacement in order to establish a norm against which mobile bearing implants can be judged.

Method: Eighteen all polyethylene tibial components were retrieved when a St Georg Sled unicompartmental replacement was being revised. This prosthesis has a biconvex femoral component and a totally flat tibia; thus point loading occurs on at implantation. The implants had been in situ between 6 and 110 months, revision was predominantly for progression of the arthritic process.

Linear wear was measured using an electronic micrometer and volumetric wear by creating a mould of the defect using dental wax, and subsequently weighing the wax.

Results: All components developed dishing which varied in orientation but matched the alignment of the femoral component. A near congruous articulation was thus produced correctly aligned for that particular arthroplasty. The mean linear penetrative wear for the group was 0.33mm (0.09mm per year) and the volumetric wear 124mm³ (26mm³ per year). The rate of wear seemed greatest during the second year.

Conclusion: The wear rate for this totally non congruous implant was much less than anticipated. The linear penetrative wear is comparable to that reported for Charnley hip replacement though more than for a fully congruent mobile UKR. The volumetric wear is much lower than that thought to cause osteolysis. The surprisingly low wear rate suggests that the need for mobile bearing UKRs, with their greater technical demands, should be questioned.

The latest government targets state that by the end of 2005 the maximum waiting time for an outpatient appointment will be 3 months. These recommendations will not only increase the size of the outpatient clinics, but also the resources required thereafter. The purpose of this study was to analyse the outcome of new knee referrals to one consultant’s knee outpatient service in order to quantify the resources required to investigate and treat these patients.

All new patients attending one consultant’s knee out-patient service in the time period January 1st 1997 to December 31st 1997 were prospectively entered into a database recording patient details, source of referral and provisional diagnosis.

Eighteen months after the time period a cohort of 200 patients was randomly selected and the notes were analysed retrospectively. The number of outpatient appointment episodes (OPAs), MRI scans, physiotherapy referrals and surgical episodes generated were recorded for each patient.

Analysis of the initial database records show that a total of 662 new knee referrals were seen in 1997. 52% (341) were made up of the five most common diagnoses, these being osteoarthritis, anterior knee pain, major anterior cruciate ligament injury, medial ligament injury and medial meniscus injury.

Retrospective analysis of the 200 patient notes revealed that these patients required a total of 511 OPAs, 38 MRI scans, 178 courses of physiotherapy and 93 surgical episodes (53 elective and 40 daycase/emergency). These figures can be extrapolated to account for the total number of patients seen:

The resource implications of a new knee referral are substantial. Extra resources must accompany each new patient, otherwise, although government targets will be reached the time taken to complete each patient’s treatment will become longer. It is imperative that before an agreement is made to see new patients the resources required to manage them are in place.