There is little published literature to support the claim that a successful total knee replacement (TKR) is predictive of future good outcomes on the contralateral side. The objective was to identify whether outcome from the first of staged TKRs could be used to predict the outcome of the contralateral TKR. This was a retrospective cohort study of 1687 patients over a 25-year period undergoing staged bilateral TKRs in a UK arthroplasty centre. A control group of 1687 patients undergoing unilateral TKR with matched characteristics was identified. Primary outcomes were satisfaction and Knee Society Score (KSS) at one year. Preoperative status was comparable for pain, ROM and KSS (mean 41, 45, 43±14). At one year follow up, dissatisfaction was similar for all groups (4% first of staged TKR, 4% second of staged TKR, 5% controls). If the first TKR had a good outcome, the relative risk of a contralateral bad outcome was 20% less than controls (95% CI 0.6–1.2). If the first TKR had a poor outcome, the risk of a second poor outcome was 4 times higher (95% CI 2.8–6.1), increasing from 6% to 27% (absolute risk). Patients undergoing the second of staged TKRs with a previous good outcome are likely to do well in their second procedure (94 in 100 will go on to have a second good outcome). Of those with a previous poor outcome, 27 in 100 will have a second poor outcome. The trend was persistent despite correcting for gender, age, BMI, and diagnosis

The primary aim of this study was to compare the knee specific functional outcome of partial compared with total knee replacement (TKR) for the management of patellofemoral osteoarthritis. Fifty-four consecutive Avon patellofemoral replacements were identified and propensity score matched to a group of 54 patients undergoing a TKR with patella resurfacing for patellofemoral osteoarthritis. The Oxford knee score (OKS), the Short Form (SF-) 12 and patient satisfaction were collected (mean follow up 9.2 years). Survival was defined by revision or intention to revise. There was no significant difference in the OKS (p>0.60) or SF-12 (p>0.28) between the groups. The TKR group was significantly less likely to be satisfied with their knee (95.1% versus 78.3%, OR 0.18, p=0.03). Length of stay was significantly (p=0.008) shorter for the Avon group (difference 1.8 days, 95% CI 0.4 to 3.2). The 10 year survival for the Avon group was 92.3% (95% CI 87.1 to 97.5) and for the TKR group was 100% (95% CI 93.8 to 100). There was no statistical difference in the survival rate (Log Rank p=0.10). The Avon patellofemoral replacement have a shorter length of stay with a functional outcome and satisfaction rate that is equal to that of TKR. The benefits of the Avon need to be balanced against the increased rate of revision when compared with TKR

The Low Contact Stress (LCS) mobile-bearing total knee replacement (TKR) was designed to minimize polyethylene wear, aseptic loosening and osteolysis. However, registry data suggests there is a significantly greater revision rate associated with the LCS TKR. The primary aim of this study was to assess long-term survivorship of the LCS implant. Secondary aims were to assess survival according to mechanism of failure and identify predictors of revision. We retrospectively identified 1091 LCS TKRs that were performed between 1993 and 2006. There was incomplete data available 33 who were excluded. The mean age of the cohort was 69 (SD 9.2) years and there were 577 TKRs performed in females and 481 in males. Mean follow up was 14 years (SD 4.3). There were 59 revisions during the study period: 14 for infection, 18 for instability, and 27 for polyethylene wear. 392 patients died during follow up. All cause survival at 10-year was 95% (95%CI 91.7–98.3) and at 15-year was 93% (95%CI 88.6–97.8). Survival at 10-years according to mechanism of failure was: infection 99% (95%CI 94–100%), instability 98% (95%CI 94–100%), and polyethylene wear 98% (95%CI92–100). Of the 27 with polyethylene wear only 19 had associated osteolysis requiring component revision, the other 8 had simple polyethylene exchanges. Cox regression analysis, adjusting for confounding variables, identified younger age was the only predictor of revision (hazard ratio 0.96, 95%CI 0.94–0.99, p=0.003). The LCS TKR demonstrates excellent long-term survivorship with a low rate of revision for osteolysis, however the risk is increased in younger patients

High tibial osteotomy (HTO) is a common procedure for treating medial compartment knee arthritis. The main goal is to reduce knee pain by transferring weight-bearing loads to the relatively unaffected lateral compartment and thus delaying the need of total knee replacement (TKR) by slowing or stopping destruction of medial compartment. Between 2002 and 2010, 34 HTO's were carried out in 32 patients (Mean age 44.2). Results were reviewed in 23 patients with an average follow-up of 10.2 years (range 6–14 years). Oxford knee score (OKS) assessment was carried out on those patients. Of the remaining 11 patients, one was excluded, 2 were lost to follow-up, and 2 had died. Five cases had TKR at an average 8.8 years since having HTO. OKS results revealed nine cases (39.1percnt;) scored (40–48) which indicate satisfactory joint function and don't require treatment. Three cases (13percnt;) scored (30–39) indicating mild to moderate arthritis. Six cases (26.1percnt;), scored (20–29) indicating moderate to severe arthritis. Five cases (21.8percnt;) scored (0–19) indicating severe arthritis. Only five patients (14.7percnt;) had TKR (6–14) years after there HTO. The majority of cases had an OKS suggesting satisfactory joint function. Even those with scores suggesting moderate to severe arthritis were able to function normally for more than 6 years. The successful outcome of HTO can be maintained for more than 6–16 years. We conclude that HTO should be recommended for the treatment of medial compartment arthritis of the knee in young and active patients for symptomatic improvement and maintenance of activity levels

By the end of training, every registrar is expected to demonstrate proficiency in total knee replacement (TKR). It is unclear whether functional outcomes for knee arthroplasty performed by training grade doctors under supervision of a consultant have equivalent functional outcomes to those performed by consultants. This study investigated the functional outcomes following TKR in patients operated on by a supervised orthopaedic trainee compared to a consultant orthopaedic surgeon. Patients undergoing surgery by a consultant (n=491) or by a trainee under supervision (n=145) between 2003 and 2006 were included. There was a single implant, approach and postoperative rehabilitation regime. Patients were reviewed eighteen months, three years and five years postoperatively. There were no significant differences in preoperative patient characteristics between the groups. There was no difference in length of stay or transfusion or tourniquet time. Both consultant (p<0.001) and trainee (p<0.001) groups showed significant improvement in AKSK and AKSF scores between preoperative and 18 month review and there was no difference in the magnitude of observed improvement between groups (AKSK p=0.853; AKSF p=0.970). There were no significant differences in either score between the groups preoperatively or at any review point postoperatively. At five years postoperative, both groups had a median OKS of 34 (p=0.921). This is the largest reported series of outcomes following primary TKR examining functional outcome linked with grade of surgeon. It shows that a supervised trainee will achieve comparable functional outcomes at up to 5 years post operatively

Tranexamic Acid (TA) has been shown to reduce transfusion rates in Total Knee Replacement (TKR) without complication. In our unit it was added to our routine enhanced recovery protocol. No other changes were made to the protocol at this time and as such we sought to examine the effects of TA on wound complication and transfusion rate. All patients undergoing primary TKR over a 12 month period were identified. Notes and online records were reviewed to collate demographics, length of stay, use of TA, thromboprophylaxis, blood transfusion, wound complications and haemoglobin levels. All patients received a Columbus navigated TKR with a tourniquet. Only patients who received 14 days of Dalteparin for thromboprophylaxis were included. 124 patients were included, 72 receiving TA and 52 not. Mean age was 70. Four patients required a blood transfusion all of whom did not receive TA (p = 0.029). Mean change in Hb was 22 without TA and 21 with (p = 0.859). Mean length of stay was 6.83 days without Tranexamic Acid and 5.15 with (p < 0.001). 15% of patients (n=11) of the TA group had a wound complication, with 40% of patients (n=21) in the non TA group (p = 0.003). There was one ultrasound confirmed DVT (non TA group). No patients were diagnosed with pulmonary embolus. In our unit we have demonstrated a significantly lower transfusion rate, wound complication rate and length of stay, without any significant increase in thromboembolic disease with the use of TA in TKR

This study assessed whether patient satisfaction with their hospital stay influences the early outcome of total knee replacement (TKR). During a five year period patients undergoing primary TKR at the study centre had prospectively outcome data recorded (n=2264). Patients with depression (p=0.04) and worse mental wellbeing (p<0.001), according to the short form (SF)-12, were more likely to be dissatisfied with their hospital stay. Decreasing level of satisfaction with their hospital stay was associated with a significantly worse post-operative OKS (p<0.001) and SF-12 score (p<0.001). Multivariable regression analysis confirmed that the patients perceived level of satisfaction with their hospital stay was an independent predictor of change in the OKS (p<0.001) and SF-12 score (p<0.001) after adjusting for confounding variables. Patient satisfaction with their TKR was significantly influenced by their hospital experience, decreasing from 96% in those with an excellent experience to 42% in those with a poor experience. Food, staff/care, and the hospital environment were the most frequent reasons of why patients rated their hospital experience as fair or poor. A patient's perception of their inpatient hospital experience after surgery is an important modifiable predictor of early functional outcome and satisfaction with TKR

The surgical treatment of unicompartmental knee osteoarthritis remains controversial. This study aims to compare the medium-term outcomes of age and gender matched patients treated with unicompartmental knee replacement (UKR) and total knee replacement (TKR). We retrospectively reviewed pain, function and total knee society scores (KSS) for every UKR and age and gender matched TKR in NHS Tayside, with up to 10 years prospective data from Tayside Arthroplasty Audit Group. KSS was compared at 1, 3 and 5 years. Medical complications and joint revision were identified. Kaplan-Meier with revision as end-point was used for implants survival analysis. 602 UKRs were implanted between 2001 and 2013. Preoperative KSS for pain and total scores were not significantly different between UKRs and TKRs whereas preoperative function score was significantly better for UKRs. Function scores remained significantly better in UKRs from preoperative until 3 years follow up. Further analysis revealed no statistically significant difference in the change of function scores in both groups over time. There was a trend for TKRs to perform better than UKRs in pain scores. Total KSS for both groups were not significantly different at any point of the 5-year study. Fewer medical complications were reported in the UKR group. Kaplan-Meier analysis showed a survival rate of 93.7% in UKRs and of 97% in TKRs (Log rank p-value = 0.012). The revision rate for UKR was twice as much as TKR. The theoretical advantages of UKR are not borne out by the findings in this study other than immediate postoperative complications

We report the largest series of periprosthetic fractures in the literature, describing the changing epidemiology and predictors of outcome. A retrospective search of prospectively compiled trauma and elective electronic databases identified 630 periprosthetic fractures presenting to the study centre between 1995 and 2010. Patient demographics, comorbidities, socioeconomic status, mechanism of injury, fracture type, classification, method of fixation, and outcome were recorded using the patients’ notes. The General Register Office for Scotland was used to obtain the mortality status of the patients. There were 276 total hip replacements (THR), 123 total knee replacements (TKR), 117 hemiarthroplasty, and 114 “other” implants. The incidence of periprosthetic fractures increased significantly during the study period for all implants: THR (p<0.001), TKR (p<0.001), hemiarthroplasty (p=0.002), and other (p=0.003). The majority of fractures were fixed by open reduction and internal fixation (72%). This failed in 14% of THR, 15% of TKR, 21% of hemiarthroplasties, and 18% of “other” implants. Isolated independent predictors of failure of fixation, after multivariate regression analysis, were increasing age, deprivation, a past medical history of asthma or chronic obstructive airways disease, osteoporosis, and steroid use (p<0.05). Failure of fixation was associated with a significantly increased one year mortality rate (OR 12.5, p=0.003). Periprosthetic fractures involving THR and TKR are becoming more prevalent. Patient demographics can be used to calculate the risk of failure of fixation, and those with an increased risk may benefit from revision of their implant, and avert the associate morbidity of failure of fixation

Two stage revision for infection is considered the gold standard with a success rate of 80–90%. Overall functional outcomes of these patients are commonly overlooked. There is a trend towards single stage revision to improve functional outcomes. We examined the functional scores of 2 stage revision for total hip arthroplasty (THR) and total knee arthroplasty (TKR). 72 revisions were identified over 9 years: 30 THR and 42 TKR. Two year survivorship was 96% in THR revision and 88% TKR revision. Five year survival was 83% and 84% respectively. 50 patients (without recurrence of infection) had recorded functional scores at a minimum of 1 year. The mean Harris-hip score (HHS) of THR was 75 (21 patients) prior to developing symptoms of infection. Once infected, the mean score fell to 46. At 1 year post revision it returned to 77. At 3 years HHS of 78 (12 patients) and at 5 yrs 62 (3 patients). The mean knee society score (KSS) of TKR was 66 (29 patients) prior to developing symptoms of infection. Once infected, the mean score fell to 34. At 1 year post revision it returned to 73. At 3 years KSS of 76 (16 patients) and at 5 years 62 (10 patients). We conclude that functional scores of staged revisions of infected THR and TKR return to pre-morbid levels within a year of completing the second stage. Although single stage revision may have a quicker return to function, by 1 year, staged revision has comparable results

There is conflicting data from small retrospective studies as to whether pre-operative mental health influences the outcome of total knee replacement (TKR). We assessed the effect of mental disability upon the outcome of TKR and whether mental health improves post-operatively. During a three year period patients undergoing TKR for primary osteoarthritis at the study centre had prospectively outcome data recorded (n=962). Pre-operative and one year short-form (SF) 12 scores and Oxford knee scores (OKS) were obtained. The mental component of the SF-12 was stratified into four groups according to level of mental disability (none ≥50, mild 40to49, moderate 30to39, severe <30). Ethical approval was obtained (11/AL/0079). Patients with any degree of mental disability had a significantly greater subjective physical disability according to the SF-12 (p=0.06) and OKS (p<0.001). Although the improvement in the disease specific score (OKS) was not affected by a patients mental health (p=0.33). In contrast the improvement of the global physical health (SF-12) for patients with a mental disability did not improve to the same magnitude (p<0.001). However, patients with mental disability, of any degree, had a significant improvement in their mental health post-operatively (p<0.0001). Despite the similar improvement in the disease specific scores and improvement in their mental health, patients with mental disability were significantly more likely to be dissatisfied with their TKR at one year (p=0.001). TKR for patients with poor mental health benefit from improvement in their mental health and in their knee function, but do have a higher rate of dissatisfaction

Anterior knee pain post Total knee Replacement (TKR) has been reported to be as high as 49%. The source is poorly understood; both the peripatellar soft tissues and the infrapatellar fat pad have been implicated. Immunohistochemical studies demonstrate hyperinnervation of the peripatellar soft tissues. In theory circumferential electrocautery denervates the patella. However there is little evidence that this practice translates into improved clinical outcomes. This study aimed to find the effect on clinical outcome, of intraoperative circumpatellar electrocautery in patients undergoing TKR. 200 patients undergoing primary TKR were randomised to circumferential circumpatellar electrocautery or nothing. Patients were assessed for Visual (VAS) for anterior knee pain and Oxford Knee Score (OKS) preoperatively, 3 months, 6 months and 1 year post-procedure. Patients and assessors were blinded to treatment allocation until the end of the study. There were 91 patients in the electrocautery group and 94 controls. The mean VAS improvement from pre-op to one year was 3.8 in both groups. The mean improvement in OKS was 16.6 points in the control and 17.7 in the electrocautery group (p= 0.40). There were no significant differences between the two groups in terms of VAS or OKS at any other time. Although previous studies have conflicting outcomes, to our knowledge this is the first prospective randomised controlled blinded trial of significant power, to evaluate the effect of peripatellar diathermy in TKR. We conclude that denervation electrocautery of the patella makes no difference to the clinical outcomes of TKR

Aim. The aim of this prospective comparative study was to evaluate the serum levels of different cytokines in patients underwent total knee replacement (TKR) and received allogeneic blood transfusion, post-operative auto-transfusion or not transfused. Material and Methods. This was a prospective non-randomized comparative study in 248 patients underwent TKR. Patient's demographic and clinical data including age, gender, body mass index (BMI), preoperative Hb value, complications were documented. The serum levels of IL-1b, IL-6, IL-8, IL-10, and TNF were measure pre-operatively, the 1st, 2nd, 3rd and 5th post-operative day. Patients were categorized in three groups; in Group 0 patients received no blood transfusion, in Group 1 patients received post-operative auto-transfusion and in Group 2 allogeneic blood transfusion was applied. Statistical analysis of the results was performed using repeated measures ANOVA. Results. Significant changes were observed in cytokines levels in Groups 1 and 2. In Group 1 (auto-transfusion) the levels of all cytokines significantly increased the 1st postoperative day, remaining above the pre-operative levels even the 5th post-operative day. In Group 2 (allogenic transfusion), although the levels of IL-6, IL-8 and IL-10 were also significantly increased the 1st postoperative day, they gradually returned to the per-operative levels by the 5th post-operative day. In Group 0 (no transfusion) the only significant increase was observed in IL-6 between pre-operative and 1st and 3rd day values. Furthermore, the area under the curve (AUC) of IL-1b, IL-6, IL-8 and IL-10 levels in Group 1 and AUC of IL-6, IL-8 and IL-10 levels in Group 2, were significantly higher compared to Group 0. There was no significant difference in post-operative patient's complications. Conclusion. According to the results of this study significant elevation of cytokine values were observed during the first five post-operative days in patients received blood transfusion after TKR. These changes were more pronounced in the auto-transfusion group

Introduction. The peri-operative analgesic management of patients having either Total Knee Replacement (TKR) or Unicompartmental Knee Replacement (UKR) is an area that continues to have prominence, driven in part by the desire to reduce hospital stay, while maintaining high patient satisfaction. This is particularly relevant in the current climate of healthcare cost savings. We evaluated the role of “top up” intra-articular local anaesthetic injection after identifying that an appreciable number of patients in the unit suffered “breakthrough pain” on the first post-op day, when the effects of local analgesia are wearing off. Method. 43 patients, who were scheduled to have a cemented Oxford UKR, were prospectively recruited and randomised. All patients had the same initial anaesthetic regime of general anaesthesia, femoral nerve block and intra-operative intra-articular infiltration of the cocktail. All patients had a 16G multi-holed epidural catheter placed intra-articularly prior to wound closure. Patients had the same operative technique, post operative rehabilitation and rescue analgesia. An independent observer recorded post-operative pain scores using a visual analogue score (1–10) every 6 hours and any rescue analgesia that was required. On the morning after surgery, 22 patients, (Group I), received 20 mls of 0.5% bupivicaine through the catheter whilst 21 patients, (Group II), had 20 mls of normal saline by the same observer, (who was blinded to the contents of the solution being injected), after which the catheter was removed. Results. When comparing these two groups there was no statistical difference found in their pain scores on the day of operation. However, patients in Group I had a significantly better pain score initially post top up and then at 6 hours (2.4 (0–8) vs 5.7 (2–9), Mann-Whitney p<0.001). This cohort of patients required less rescue analgesia (22% vs 75%, Mann-Whitney p<0.001). In addition, Group I had statistically significant higher patient satisfaction outcome scores after the infiltration, (p<0.001), with 16 reporting very good satisfaction in comparison to 1 in Group II. There were no complications in either group. Discussion. Our study has shown that injection of local anaesthesia via an intra-articular catheter does reduce pain scores when compared to placebo. This implies that this technique may have a role in providing optimal pain relief after UKR

Background. Tranexamic acid (TA) in total knee replacement surgery (TKR) has shown marked reduction in bleeding and blood transfusion. There are little data on TA in revision TKR. From February 2008 all patients having primary or revision TKR received TA 10mg/kg × 2. We whished to evaluate the effect and possible complications of TA. Patients and Methods. 49 patients had revision TKR from January to August 2010. 21 patients (group I) operated before the regular use of TA were compared to 28 patients (group II) receiving TA. The groups were compared according to bleeding, blood transfusion, postoperative complication and type of revision. Revision TKR was compared to 157 primary TKR (94 operated without TA (group III) and 63 who received TA (group IV). Results. Group I: Preoperative Hgl 13.6g/dl (9.2–15.3), reduction in hgl 3.9g/dl (1.0–5.7), bleeding 1040ml (380–2100). 6 patients (28.6%) needed blood transfusion. 7 patients were admitted to cell-saver and were given mean 400 ml blood (150–730). There were 6 revisions from uni-prostheses to TKR and 15 was revision of TKR. There was no difference in bleeding between this to groups (980ml/1030ml). Group II: Preoperative Hgl 14.2g/dl (11.2–18.6), reduction in hgl 3.3g/dl (1.4–8.3), bleeding 490ml (120–1050) (47.1% reduction in bleeding volume (p<0,002)). One patient (3.4%) needed blood transfusion. There was 8 revisions from uni-prostheses to TKR and 21 was revision of TKR. There was no difference in bleeding between this two groups (510ml/570ml). Group III: Preoperative Hgl 14.2g/dl (10.1–17.4), reduction in Hgl 3.5g/dl (1.1–7.7), bleeding 1048ml (50–2230). 15 patients (16%) needed blood transfusion. Group IV: Preoperative Hgl 13.7g/dl (11.6–18.1), reduction in Hgl 2.76g/dl (1.2–4.8) (p=0,014), bleeding 370ml (130–960) (64.5% reduction in volume (p<0,002)). 2 patients (3%) needed blood transfusion. (p=0,004)). There was no statistically significant difference in bleeding between primary and revision TKR (p=0.18). Conclusion. Our results shows that TA reduces bleeding and the need for blood transfusion markedly. The TA groups had no increase in any complications

Due to increased life expectancy of human population, the amount of total knee replacements (TKR) is expected to increase. TKR reached a high grade of quality and safety, but most often it fail because of aseptic implant loosening caused by polyethylene (PE) wear debris. Wear is generated at the articulating surfaces, e.g. caused by three body particles, like bone fragments or bone cement particles. The aim of this experimental study was to compare the wear of tibial PE inserts combined with metallic and ceramic femoral components at three body wear situation induced by polymethylmethacrylate (PMMA) and zirconia (ZrO2) particles from the bone cement. Wear testing was performed for 5 Mio load cycles, using tibial standard PE inserts combined with the same CR femoral component, in two different materials, Cobalt Chromium (CoCrMo) and Biolox delta ® ceramic (Multigen Plus Knee System, Lima Corporate, Italy). A knee wear simulator, according to ISO 14243 (EndoLab GmbH, Rosenheim, Germany), was used to carry out the tests. The tests were performed in temperature-controlled test chambers at 37 °C, containing calf serum with a protein content of 30 g/l. Polymethylmethacrylate (PMMA) and zirconia (ZrO2) bone cement particles (Palacos R ®) were manufactured to a size of 30 μm. The three body particles were added at all stations onto the articulating surface of the tibial PE insert (7mg per condyle) at every 500,000 cycles. Wear was determined gravimetrically and the surfaces of tibial inserts were analysed by scanning electron microscope (SEM) after finishing the 5 million cycles. Furthermore, roughness of the PE insert surfaces and the articulating surfaces of the different femoral components were detected and the PE wear particles were analysed by SEM. The average gravimetrical wear rates of the tibial PE inserts in combination with CoCr and Biolox delta ® ceramic femoral components amounted to 6.4 ± 0.9 mg and 2.6 ± 0.4 mg per million cycles, respectively. Beside bone cement particles on the articulating surface of the PE inserts, polished surfaces and scratches were detected by SEM. In comparison to the untreated surfaces of the PE inserts at both material pairings the surface roughness at the articulating areas showed deep scratches and polished regions. Analyses of the metallic femoral components showed scratches at the articulating surfaces, none on ceramics. The present study pointed out the effect of femoral component material in an abrasive three body wear situation on the wear properties of TKR. The wear simulator tests showed that wear of PE inserts under three body wear conditions, in combination with ceramic femoral components, was significantly lower than with metallic femoral components. With regard to anti-allergic properties, ceramic femoral components are promising products for TKR

Introduction. Femorotibial malalignment exceeding ±3° is a recognised contributor of early mechanical failure after total knee replacement (TKR). The angle between the mechanical and anatomical axes of the femur remains the best guide to restore alignment. We investigated where the femoral head lies relative to the pelvis and how its position varies with respect to recognised demographic and anatomic parameters. We have tested the hypothesis of the senior author that the position of the centre of the femoral head varies very little, and if its location can be identified, it could serve to outline the mechanical axis of the femur without the need for sophisticated imaging. Patients & Methods. The anteroposterior standing, plain pelvic radiographs of 150 patients with unilateral total hip replacements were retrospectively reviewed. All patients had Tönnis grade 0 or 1 arthritis on the non-operated hip joint. All radiographs were obtained according to a standardised protocol. Using the known diameter of the prosthetic head for calibration, the perpendicular distance from the centre of the femoral head of the non-operated hip to the centre of pubic symphysis was measured with use of TraumaCad software. Anatomic parameters, including, but not limited to, the diameter of the intact femoral head, were also measured. Demographic data (gender, age, height, weight) were retrieved from our database. Results. There were 72 men and 78 women with a mean age of 67.0 years. The mean distance of the centre of the femoral head to the pubic symphysis was 89.1 mm (standard deviation [SD], 5.8 mm). This distance was higher in men (mean, 90.5 mm; SD, 5.6 mm) than in women (mean, 87.7 mm; SD, 5.8 mm) (p=0.003). No statistically significant correlations between this distance and body-mass index or age (p=0.57 and p=0.28, respectively) were revealed. However, height was strongly correlated with this distance (r=0.52, p < 0.01), as was the diameter of the femoral head (r=0.61, p < 0.01). The latter was significantly larger in men than in women (p < 0.01). Conclusion. This is the first study to demonstrate that the position of the centre of the femoral head has very little variability, irrespective of patient age or body-mass index. As expected, it varies with patient's height and gender. Although statistically significant, the difference between genders is < 3 mm and can be explained by the smaller femoral head size of females. Our findings should prove useful during TKR surgery, as they facilitate intra-operative identification of the centre of the femoral head. Based on these results, simple trigonometry shows that if a surgeon measures 9 cm from the symphysis pubis, a line from this point to the centre of the knee will be within 2° and 2.2° of the true mechanical axis in 98% (i.e. ± 3 SD of the mean) of male and female patients, respectively

Stable fractures of the ankle can be successfully treated non-operatively by a below-knee plaster cast. In some centres, patients with this injury are routinely administered low-molecular-weight heparin, to reduce the risk of deep-vein thrombosis (DVT). We have assessed the incidence of DVT in 100 patients in the absence of any thromboprophylaxis. A colour Doppler duplex ultrasound scan was done at the time of the removal of the cast.

Five patients did develop DVT, though none had clinical signs suggestive of it. One case involved the femoral and another the popliteal vein. No patient developed pulmonary embolism. As the incidence of DVT after ankle fractures is low, we do not recommend routine thromboprophylaxis.

There is a high risk of venous thromboembolism when patients are immobilised following trauma. The combination of low-molecular-weight heparin (LMWH) with graduated compression stockings is frequently used in orthopaedic surgery to try and prevent this, but a relatively high incidence of thromboembolic events remains. Mechanical devices which perform continuous passive motion imitate contractions and increase the volume and velocity of venous flow.

In this study 227 trauma patients were randomised to receive either treatment with the Arthroflow device and LMWH or only with the latter. The Arthroflow device passively extends and plantarflexes the feet. Patients were assessed initially by venous-occlusion plethysmography, compression ultrasonography and continuous wave Doppler, which were repeated weekly without knowledge of the category of randomisation. Those who showed evidence of deep-vein thrombosis underwent venography for confirmation. The incidence of deep-vein thrombosis was 25% in the LMWH group compared with 3.6% in those who had additional treatment with the Arthroflow device (p < 0.001). There were no substantial complications or problems of non-compliance with the Arthroflow device. Logistic regression analysis of the risk factors of deep-vein thrombosis showed high odds ratios for operation (4.1), immobilisation (4.3), older than 40 years of age (2.8) and obesity (2.2).