Aims. Patients who sustain neck of femur fractures are at high risk of malnutrition. Our intention was to assess to what extent malnutrition was associated with worse patient outcomes. Methods. A total of 1,199 patients with femoral neck fractures presented to a large UK teaching hospital over a three-year period. All patients had nutritional assessments performed using the Malnutrition Universal Screening Tool (MUST). Malnutrition risk was compared to mortality, length of hospital stay, and discharge destination using logistic regression. Adjustments were made for covariates to identify whether malnutrition risk independently affected these outcomes. Results. Inpatient mortality was 5.2% (35/678) in the group at low risk of malnutrition, 11.3% (46/408) in the medium-risk group, and 17.7% (20/113) in the high-risk group. Multivariate analysis showed each categorical increase in malnutrition risk independently predicted inpatient mortality with an odds ratio (OR) of 1.59 (95% confidence interval (CI) 1.14 to 2.21; p = 0.006). An increased mortality rate persisted at 120 days post-injury (OR 1.64, 95% CI 1.20 to 2.22; p = 0.002). There was a stepwise increase in the proportion of patients discharged to a residence offering a greater level of supported living. Multivariate analysis produced an OR of 1.34 (95% CI 1.03 to 1.75; p = 0.030) for each category of MUST score. Median length of hospital stay increased with a worse MUST score: 13.9 days (interquartile range (IQR) 8.2 to 23.8) in the low-risk group; 16.6 days (IQR 9.0 to 31.5) in the medium-risk group; and 22.8 days (IQR 10.1 to 41.1) in the high-risk group. Adjustment for covariates revealed a partial correlation coefficient of 0.072 (p = 0.008). Conclusion. A higher risk of malnutrition independently predicted increased mortality, length of hospital stay, and discharge to a residence offering greater supported living after femoral neck fracture. Cite this article: Bone Joint J 2021;103-B(1):164–169

We report a cost-effectiveness analysis of Primary Total Ankle Replacements (TAR). In addition, we looked for factors that could be predictors of increased gain in Quality-Adjusted Life Years (QALYs). Pre-operative and six-month post-operative data for TAR was obtained over seven-and-a-half-years in NHS Lothian. The EuroQol general health questionnaire (EQ-5D-3L) measured health-related Quality of Life and the Manchester-Oxford Foot Questionnaire (MOXFQ) measured joint function. Predictors, tested for significance with QALYs gained, were pre-operative scores and demographic data including age, gender, BMI and Deprivation category. Continuous variables were assessed with Pearson correlation coefficients, Deprivation and BMI categories with Boxplots and gender with the Mann-Whitney U test. The 74-patient cohort [Mean age 68.03 (SD 8.61), 60.8% male] had 49% classed as obese or higher. Cost per QALY gained was £3841, rising to £9202 when annual 3.5% reduction in health gains and 1.9% revision rates were included. Lower pre-operative EQ-5D-3L index correlated significantly with increased QALYs gained (p <0.01), all other predictors returned insignificant results (p >0.05). Primary TAR has proven very cost-effective in treating end-stage ankle arthritis. Pre-operative EQ-5D-3L is the most promising predictor of QALYs gained identified

Though knee osteoarthritis (OA) is diagnosed and monitored radiographically, full thickness cartilage loss (FTCL) has rarely been correlated with radiographic classification. This study aims to analyse which classification system correlates best with FTCL and assessing their reliability. Prospective study of 300 consecutive patients undergoing total knee arthroplasty (TKA) for OA. Two blinded examiners independently graded preoperative radiographs using 5 systems: Kellgren-Lawrence (KL); International Knee Documentation Committee (IKDC); Fairbank; Brandt; and Ahlback. Interobserver agreement was assessed using the intraclass correlation coefficient. Intraoperatively, anterior cruciate ligament (ACL) status and FTCL in 16 regions of interest were recorded. Radiographic classification and FTCL were correlated using the Spearman correlation coefficient. On average, each knee had 6.8±3.1 regions of FTCL, most common medially. The commonest patterns of FTCL were medial with patellofemoral (48%) and tricompartmental (30%). ACL status was associated with pattern of FTCL (p=0.02). All classification systems demonstrated moderate ICC, but this was highest for IKDC: whole knee 0.68 (95%CI 0.60–0.74); medial compartment 0.84 (0.80–0.87); and lateral compartment 0.79 (0.73–0.83). Correlation with FTCL was strongest for Ahlback (Spearman rho 0.27–0.39) and KL (0.30–0.33), though all systems demonstrated medium correlation. The Ahlback was the most discriminating in severe OA. Osteophyte presence in the medial compartment had high positive predictive value for FTCL, but not in the lateral compartment. The Ahlback and KL systems had the highest correlation with confirmed cartilage loss. However, the IKDC system displayed best interobserver reliability, with favourable correlation with FTCL in medial and lateral compartments, though less discriminating in severe disease

The objective of this study was to compare differences in alignment following robotic arm-assisted bi-unicompartmental knee arthroplasty (Bi-UKA) and conventional total knee arthroplasty (TKA). This was a prospective, randomised controlled trial of 70 patients. 39 TKAs were implanted manually, as per standard protocol at our institution, and 31 Bi-UKA patients simultaneously received fixed-bearing medial and lateral UKAs, implanted using robotic arm-assistance. Preoperative and 3-month postoperative CT scans were analysed to determine hip knee ankle angle (HKAA), medial distal femoral angle (MDFA), and medial proximal tibial angle (MPTA). Analysis was repeated for 10 patients by a second rater to validate measurement reliability by calculating the intra-class correlation coefficient (ICC). Mean change in HKAA towards neutral was 2.7° in TKA patients and 2.3° in Bi-UKA patients (P=0.6). Mean change in MDFA was 2.5° for TKA and 1.0° for Bi-UKA (P<0.01). Mean change in MPTA was 3.7° for TKA and 0.8° for Bi-UKA (P<0.01). Mean postoperative MDFA and MPTA for TKAs were 89.8° and 89.6° respectively, indicating orientation of femoral and tibial components perpendicular to the mechanical axis. Mean postoperative MDFA and MPTA for Bi-UKAs were 91.0° and 86.9° respectively, indicating a more oblique joint line orientation. Inter-rater agreement was excellent (ICC>0.99). Early functional activities, according to the new Knee Society Scoring System, favoured Bi-UKAs (P<0.05). Robotic arm-assisted, cruciate-sparing Bi-UKA better maintains the natural anatomy of the knee in the coronal plane and may therefore preserve normal joint kinematics, compared to a mechanically aligned TKA. This has been achieved without significantly altering overall HKAA

Cam type femoroacetabular impingement (FAI) is due to an aspheric femoral head, which is best quantified by the alpha angle described on MRI and CT-scan. Radiographic measurement of the alpha angle is not well codified and studies from the literature cannot conclude on the best view to measure it. Most authors also describe a mixed type FAI which associates an aspheric femoral head with an excessive anterior acetabular coverage of the femoral head. Anterior center edge (ACE) angle has been described on the false profile view to measure anterior acetabular coverage in hip dysplasia and has never been evaluated in FAI. In this study, we developed a new lateral hip view which associates a lateral view of the femoral neck and a false profile view of the acétabulum, which we called profile view in impingement position (PVIP). Twenty six patients operated for FAI had CT-scan, the PVIP and the false profile view of one or two hips according to pain. A control group of 19 patients who did not suffer from the hip had the PVIP. Alpha angles were measured twice on 17 CT scan of FAI patients by two observers and compared with the alpha angles measured on the corresponding hip PVIP by a correlation analysis. Alpha angles were measured twice on 45 PVIP in FAI patient and on 19 PVIP in the control group by three observers. ACE angles were measured once on 15 PVIP and on 15 false profile views. Means were compared by two tail paired t-tests, intra- and inter-observer reliability were measured by intraclass correlation coefficient. Mean alpha angle on CT scan was 65.8° and 65.6° for observers 1 and 2 respectively (p>0.05). It was 63.6° and 64.3° on the PVIP (p>0.05). No significant difference was found between CT scan and radiographic measurements, and Pearson's correlation coefficients were good at 0.74 and 0.8. ICC was 0.86 for inter-rater reliability, and 0.91 for intra-rater reliability for CT-scan alpha angle measures. ICC for PVIP measures varied from 0.82 to 0.9 for intra-rater reliability and from 0.6 to 0.9 for inter-rater reliability. Mean alpha angle measured on PVIP in FAI patients was 63.3° and was 44.9° in control subjects and the difference was significant (p<0.001) for the three observers. None of the FAI patients and 88% of the control subjects had an alpha angle < 50°. Mean ACE angle was 26.8° on PVIP and 32.8° on the false profile view, the difference was significant (p=0.015), and the Pearson's correlation coefficient was moderate (r=0.58). The PVIP is a reliable radiographic view to measure the alpha angle. It allows a good quantification of the alpha angle comparable to CT-scan measurements and permits to differentiate patients from control subjects. PVIP is not a good view to quantify anterior edge angle probably because of acetabular retroversion due to the hip flexion needed in this view. Mean ACE angle measured on the false profile view in FAI patient was comparable to ACE angle in general population reported in the literature

25–40% of unicompartmental knee replacement (UKR) revisions are performed for unexplained pain possibly secondary to elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on cancellous bone strain in a finite element model (FEM) of a cemented fixed bearing medial UKR, validated using previously published acoustic emission data (AE). FEMs of composite tibiae implanted with an all-polyethylene tibial component (AP) and a metal backed one (MB) were created. Polyethylene of thickness 6–10mm in 2mm increments was loaded to a medial load of 2500N. The volume of cancellous bone exposed to <−3000 (pathological overloading) and <−7000 (failure limit) minimum principal (compressive) microstrain (µ∊) and >3000 and >7000 maximum principal (tensile) microstrain was measured. Linear regression analysis showed good correlation between measured AE hits and volume of cancellous bone elements with compressive strain <−3000µ∊: correlation coefficients (R= 0.947, R2 = 0.847), standard error of the estimate (12.6 AE hits) and percentage error (12.5%) (p<0.001). AP implants displayed greater cancellous bone strains than MB implants for all strain variables at all loads. Patterns of strain differed between implants: MB concentrations at the lateral edge; AP concentrations at the keel, peg and at the region of load application. AP implants had 2.2 (10mm) to 3.2 (6mm) times the volume of cancellous bone compressively strained <−7000µ∊ than the MB implants. Altering MB polyethylene insert thickness had no effect. We advocate using caution with all-polyethylene UKR implants especially in large or active patients where loads are higher

Aims

The aims of this study were to identify means to quantify coronal plane displacement associated with distal radius fractures (DRFs), and to understand their relationship to radial inclination (RI).

Leg length discrepancy (LLD) can adversely affect functional outcome and patient satisfaction after total hip arthroplasty. We describe a novel intraoperative technique for femoral component insertion. We aimed to determine if this technique resulted in the desired femoral placement, as templated, and if this was associated with a reduced LLD. A series of fifty consecutive primary total hip replacements were studied. Preoperative digital templating was performed on standardised PA radiographs of the hips by the senior surgeon. The preoperative LLD was calculated and the distance from the superior tip of the greater trochanter to the predicted shoulder of the stem was calculated (GT-S). Intraoperatively, this length was marked on the rasp handle and the stem inserted to the predetermined level by the surgeon. This level corresponded to the tip of the greater trochanter and formed a continuous line to the mark on the rasp handle. Three independent blinded observers measured the GT-S on the postoperative radiographs. We assessed the relationship between the senior author's GT-S (preoperative) and the observers' GT-S (postoperative) using a Person correlation. The observers also measured the preoperative and postoperative LLD, and the inter-observer variability was calculated as the intra-class correlation coefficient. There was a strong correlation of preoperative and postoperative GT-S (R=0.87), suggesting that the stem was inserted as planned. The mean preoperative and postoperative LLD were −4.3 mm (−21.4–4) and −0.9 mm (−9.8–8.6), respectively (p<0.001). This technique consistently minimised LLD in this series. This technique is quick, non-invasive and does not require supplementary equipment

To validate the Modified Forgotten Joint Score (MFJS) as a new patient-reported outcome measure (PROM) in hip and knee arthroplasty (THR/TKR) against the UK's gold standard Oxford Hip and Knee Scores (OHS/OKS). The MFJS is a new assessment tool devised to provide a greater discriminatory power, particularly in well performing patients. It measures an appealing concept; the ability of a patient to forget about their artificial joint in everyday life. Postal questionnaires were sent out to 400 THR and TKR patients who were 1–2 years post-op. The data collected from the 212 returned questionnaires was analysed in relation to construct and content validity. 77 patients took part in a test-retest repeatability assessment. The MFJS proved to have an increased discriminatory power in high-performing patients in comparison to the OHS and OKS, highlighted by its more normal frequency of distribution and reduced ceiling effects. 30.8% of patients (n=131) achieved excellent OHS/OKS scores of 42–48 this compared to just 7.69% of patients who achieved a proportionately equivalent MFJS score of 87.5–100. The MFJS proved to have an increased test-retest repeatability based upon its intra-class correlation coefficient of 0.97 compared to the Oxford's 0.85. The MFJS provides a more sensitive tool in the assessment of well performing hip and knee arthroplasties in comparison to the OHS/OKS. The MFJS tests the concept of awareness of a prosthetic joint, rather than pain and function and therefore should be used as adjunct to the OKS/OHS

Introduction. One of the most common complications of ceramic on ceramic hip replacement is squeaking. The association of Accolade stem and Trident acetabular system has been reported to have squeaking incidence of up to 35,6%. There is doubt if this phenomenon occurs due to: the stem titanium alloy, the V40 femoral neck, the recessed liner of the trident cup or even the mal-seating of the trident insert on the cup. Objectives. Primary: The purpose of the present study was to determine the incidence of squeaking in association with the use of Exeter stem and Trident ceramic acetabular system. Secondary: Analysis of the correlation of the cup abduction angle and squeaking. Methods. During the period from March 2004 to December 2008, two surgeons performed 87 total hip arthroplasties in 77 patients with use of a ceramic-on-ceramic bearing (Exeter stem, alumina head, Trident ceramic acetabular system). Seventy six patients (86 THA) were available for review after at least 18 months follow-up. The incidence of squeaking and other noises was analyzed. Cup abduction angle was measured. The Pearson correlation coefficient was used to determine if a correlation existed between the cup abduction angle and squeaking. Results. The incidence of squeaking was 2,63% (2 patients). Both patients reported a “click” noise in hyperextension of the hip. The mean abduction angle was 44 degress (35–60), and 48 degrees (46 and 50) on the squeaking group. There was no statistically significant difference in the in the mean cup inclination between squeaky and quiet hips. Conclusion. The incidence of squeaking in association with the use of Exeter stem and Trident ceramic acetabular system was 2,63%. There was no correlation of the cup abduction angle and squeaking

Aims

We introduced a self-care pathway for minimally displaced distal radius fractures, which involved the patient being discharged from a Virtual Fracture Clinic (VFC) without a physical review and being provided with written instructions on how to remove their own cast or splint at home, plus advice on exercises and return to function.

Aims

Frailty greatly increases the risk of adverse outcome of trauma in older people. Frailty detection tools appear to be unsuitable for use in traumatically injured older patients. We therefore aimed to develop a method for detecting frailty in older people sustaining trauma using routinely collected clinical data.

Introduction. High Tibial Osteotomy has become an increasingly popular management option for patients with painful medial compartment osteoarthritis. The Fujisawa method used to calculate the angle of correction is well-documented but there have been no studies to look at the reliability and accuracy of web-based systems to calculate this angle. Patients and Methods. Patients undergoing valgus high tibial osteotomy between October 2004 and February 2010 who had full-length lower-limb views on the Picture Archiving and Communications System (PACS). The Fujisawa angle and length of osteotomy were calculated by the surgeon and two Orthopaedic registrars who had been appropriately trained. Results. Thirty X-rays were reviewed in 28 patients. Mean difference between measurements was 0.43 mm (SD 2.45) There was a statistically significant correlation between all three raters (P < 0.001). The greatest correlation was between the Consultant and the more senior trainee (r=0.86) with the lowest correlation between the Consultant and the more junior trainee (r=0.70). Concordance correlation coefficient between raters varied from 0.81 to 0.63. Bland-Altman plot of agreement between the Consultant and senior trainee was excellent showing only two values lying outside 1.96 SD. Discussion. Comparison of measurements between raters showed increased accuracy with greater experience of the measurement technique. Despite this we show high correlation between raters with measurement accuracy of all raters found within clinically acceptable limits (< 1mm). Conclusion. Measurement of tibial osteotomy using the fujisawa method on a web-based X-ray interpretation system is accurate and reliable

Introduction. Dislocation following total hip arthroplasty THA is a major short term complication not infrequently resulting in revision arthroplasty. Malposition of the acetabular component in THA results in a higher rate of dislocation as well as increased wear and osteolysis. The aim of this study was to assess the effect of mode of fixation on positioning of the acetabular component. Patients, materials and methods. For all THAs performed at our hospital in 2008, angle of acetabular inclination was measured using PACS by two independent observers. Interobserver and intraobserver reliability were assessed (Pearson's correlation coefficient, r). We determined whether the number of acetabular components outside the target angle range (eg:45±5°) was significantly different between cemented and cementless THA (chi squared test). An enquiry was made to the National Joint Registry (NJR) in respect to incidence of revision for dislocation of THA using cemented and cementless acetabular components, 2004–2009. Results. During 2008 126 THA were performed, 80 cemented and 46 cementless. There was good reliability of angle measurement (interobserver: r=0.89; intraobserver: r=0.87 and 0.97). More cemented acetabular components were within target angle range compared to cementless (cemented 32/80, cementless 29/46; chi squared=6.39, p<0.05). Using data from NJR comparing the number of primary hip replacement operations with number of revisions due to dislocation found a higher rate for cementless THA, 0.381% (266/69,822) than for cemented, 0.282% (262/92,928) (Odds ratio: 1.35 (95% CI 1.14–1.60; P<0.05). Conclusion. Positioning of the acetabular component is more difficult when using cementless systems as implant position is determined by orientation of reaming whereas with cement there is potential for fine implant position adjustment on insertion. The choice of a cementless acetabular component significantly increases the incidence of dislocation post THA. Acetabular component malposition is likely to be a factor in this increased incidence

Background. Overlooked compartment syndrome represents a devastating complication for the patient. Invasive compartment pressure measurement continues to be the gold standard. However, repeated measurements in uncertain cases may be difficult to achieve. We developed a new, noninvasive method to assess tissue firmness by pressure related ultrasound. Methods. Decreased tissue elasticity by means of rising compartment pressures was mimicked by infusion of saline directly into the anterior tibial compartment of 6 human specimens post mortem. A pressure transducer (Codman) monitored the pressure of the anterior tibial compartment. A second transducer was located in a saline filled ultrasound probe head to allow a simultaneous recording of the probe pressure provoked by the user. The ultrasound images were generated at 5 and 100mmHg probe pressures to detect the tissue deformity by B-mode ultrasound. The fascial displacement was measured before and after compression (d). Subsequently, increments of 5mmHg pressure increases were used to generate a standard curve (0–80mmHg), thus mimicking rising compartment pressures. The intra-observer reliability was tested using 10 subsequent measurements. A correlation was determined between d and the simulated intacompartmental pressure (ICP) in the compartment. The Pearson correlation coefficient (r) was calculated. The reliability determined by the kappa value and a regression analysis was performed. Results. With rising compartmental pressure, a concordant consistent correlation between d and ICP occurred. The Pearson coefficient was significant at r=0.979 and the intra-observer value kappa (k) showed a statistically good reliability (k10=0.73 and k70=0.79). Within a pressure ranging from 5–35mmHg there was an almost linear behavior, with decreasing elasticity and tissue movement in case of raising ICP. Conclusions. Pressure related ultrasound emphasized as a reliable tool to determine the correlation between the measured compartmental displacement and the raising intracompartmental pressures. This may help to improve the clinical assessment of the compartment elasticity by the physician. Further studies are required to investigate whether the good correlation also applies for the clinical scenario. However, this new method may be useful to monitor trends in the compartment pressures and may help to avoid delayed decision of fasciotomy

Aims

The last decade has seen a marked increase in surgical rib fracture fixation (SRF). The evidence to support this comes largely from retrospective cohorts, and adjusting for the effect of other injuries sustained at the same time is challenging. This study aims to assess the impact of SRF after blunt chest trauma using national prospective registry data, while controlling for other comorbidities and injuries.

Aims and objectives. The aim of this study was to statistically analyse the calcaneal fractures occurring in the community and distribution within the various age groups divided into decades. Methods and materials. Records of calcaneal fractures were retrieved from the audit department of the hospital using the various codes to identify patients reviewed in the clinics or admitted to the hospital between 1997 and 2009. The data collected included the total number of calcaneal fractures, total number in either gender, age at the time of incident, month of the year the incident occurred. Annual distribution of incidence of forearm fractures was calculated for every year and every month of the year. The age of the patients was divided into decades. Linear regression analysis and correlation coefficients were calculated between the incidence of fractures and different variables including age, gender and the time of the injury. Results. A total of 770 fractures were calculated including 511 males and 259 females (M/F=1.97). The average age of was 43.17 years (males=39.9 yrs, females=49.7 years). In both the sexes, there was a linear increase in the incidence of fractures in the first three decades of life with the rate of increase in males (R=0.999, r2=0.99) being 3 times that of females (R=0.96, r2=0.92). The incidence in females remained almost constant from 3rd decade to the 9th decade. The incidence in males reached a peak in the 3rd decade and then decreased steadily until the 10th decade. The incidence of fractures in females equalled that of males in the 8th decade; after which the incidence in males fell below females. There was a strong correlation between the increase in the incidence of fractures from February to August (R=0.9, r2=0.81) every year, after which the incidence reduced in the following months. There was a weak correlation between the increase in fractures from 1997 to 2009. Conclusion. There is a significant increase in the incidence of calcaneal fractures in the first three decades of life in both males and females. In males, the rate of increase in fractures is almost thrice than that of females. It can be said that men in their late twenties are more prone to sustain calcaneal fractures than any other age group or females. More injuries should be expected in August compared to the other months of the year. Further studies need to be done to look into the mechanism of injury. This could be helpful in prevention and reduction of the fracture incidence in the young and active age groups

Introduction. Surgical site infections (SSI) are related to a surgical procedure and affect the surgical wound or deeper tissues. With continuing emphasis on clinical governance and quality control, there is increasing demand from both patients and government for methods of assessing surgical results. Rates of morbidity and mortality may play important roles in these assessments. When crude comparisons between hospitals in the incidence of SSI are made, these should at least be stratified by the type of procedure. The aim of this study is to fix SSI incidence in relation to surgical procedure. Methods. This report contains data of 19.948 procedures collected from 1996 to 2008 at a Specialist Orthopaedic Hospital and analyzed by a specific software designed for the study of infection in orthopaedic and trauma surgery. The SSI surveillance is focused on categories of surgical procedure (Hip Arthroplasty, Knee Arthroplasty, Spine Surgery and Hip Fracture Surgery) with each category containing a defined set of similar procedures. A basic of demographic data and details about operation itself are collected for each procedure. Patients are followed up throughout their hospital stay and after hospital discharge. We present the incidence of SSI by risk group and surgical procedure. SSI are categorized in type, moment of diagnosis and micro-organisms reported. Analysis of the data was performed (SPSSv15.0 ®). Statistical methods used to determine significance were the independent samples t test, Pearson X2 test, Odds ratio and Spearman correlation coefficient, with a significance level of p<0,05. Results. Rates of SSI are highest in hip hemiarthroplasty after fracture and in hip and knee revision procedures. Rates of SSI increase with the number of risk factors present in the patient, especially after fracture procedures. The most common infecting micro-organism was coagulase-negative staphylococcus, followed by Staphylococcus aureus, enterococci and streptococci. 38% of the infections arise after one year of surveillance. Conclusions. Our results confirm difference in rates of SSI depending of surgical procedure in orthopaedic and trauma surgery. We believe that our decision to monitor infection with a long term follow up it's the better way to avoid under-reporting of infection. Our study has also demonstrated the extent to which the emerging problem of infection due to MRSA has affected orthopaedic surgery. The risk of acquiring SSI caused by MRSA was particularly high in patients after hip fracture surgery. Rates of SSI increase with the number of risk factors present in the patient, especially after fracture procedures. Globally, the most common infecting micro-organism was coagulase-negative staphylococcus, followed by Staphylococcus aureus, enterococci and streptococci. 38% of the infections arise after one year of surveillance

Purpose. The purpose of this retrospective study was to investigate the acetabular morphology of pincer impingement hips in order to better understand damage pattern in these patients. We compared MRI measurements made at different postions from anterior to posterior on the acetbulum in patients with pure pincer type FAI to those made in patients with pure cam-type to collect parameters that may be useful in the diagnosis and classification of pincer impingement. Material and Methods. From an initial consecutive retrospective population of 1022 patients that underwent MRI with clinical impingement signs 78 hips which were selected with as clear cam (n=57) or pincer (n=21) impingement on plain radiographics. On these MR Imaging was performed with a 1.5-Tesla system. For analysis, a lateral angle of overcoverage on coronal MRI (MR_LCE), the MR extrusion index and the alpha angle (after Nötzli) were used. In addition to these the gamma angle, the acetabular depth and the angle of lateral acetabular overcoverage were described clock-wise on 7 radial slides from anterior to posterior. These were compared between the cam and pincer population using students-t-test. Measurements were obtained by two observers and inter-observer variability was assessed. Results. The acetabular depth showed in all 7 positions significant smaller values for pincer-type in comparison to cam-type impingement. Highest difference was found is superior-posterior position. The acetabular angle is also significant smaller for pincer than for cam in all radial positions. Highest difference of the acetabular angle is located in superior (pincer −102.93°/cam 109.62°) and anterior-superior position (pincer 102.48°/cam 108.77 °). The gamma angle showed significant differences in all radial positions except anterior position. The highest difference is located in superior-posterior position (pincer 86.18 °/cam 08.77°). The mean MR extrusion index was significant lower for pincer type (12.73%) compared to cam-type patients (17.76%) (p=0.004). LCE angle and extrusion index on MRI displayed a Person correlation coefficient of 0.920. The correlation of the acetabular depth and angle was 0.638. Conclusion. There are several morphological differences between pincer and cam acetabuli: They are significantly deeper in all radial positions than cam hips. They tend to have greater retroversion and have smaller gamma angles. Our results suggest that the superior-posterior quadrant displays greater coverage in pincer hips than cam hips, and therefore damage to the labrum and cartilage surface may extend further into the posterior portion of the acetabulum in pincer hips than in cam hips

Introduction. Malrotation following total knee replacement is directly related to poor outcome. The knowledge of proximal and distal rotational axes and angles of the femur is therefore of high importance. The aim of the study was to determine whether the most used proximal and distal femoral angles; femoral anteversion angle (FAA) and posterior condylar angle (PCA) were different within individuals, between right, left and gender. As well, we studied whether the “inferior condylar angle” is correlated to the PCA and therefore useful in determining the rotation of the distal femur. Material and Methods. From 36 cadavers the femora were obtained and after removing the soft tissue a Computed Tomography (CT) scan was made. Three angles were measured: (i) the FAA between femoral columnar line (FHNL) and posterior condylar line (PCL), (ii) the PCA between anatomical transepicondylar line (TEL) and PCL, (iii) the inferior condylar angle (ICA) between the TEL and inferior condylar line (ICL). Statistical analysis of comparative relationships between the different angles was examined by calculating correlation coefficients and a paired t-test. Results. The mean FAA, PCA and ICA for the whole group were respectively 12.0 degrees (range 0.2–31.6, SD 8.3, 95% CI 9.6–14.4), 4.8 degrees (range 0.9–9.6, SD 2.3, 95% CI 4.1–5.4) and 4.5 degrees (range 0.1–9.8, SD 2.1, 95% CI 3.9–5.1). A strong correlation of the FAA was found within the total group and left versus right (r = 0.82; p = 0.00). A weaker relationship was found for the total group of the PCA measurements (r = 0.59; p = 0.00). When FAA compared to the PCA subdivided in only sexes, there is a weak correlation for the female group (r = 0.54; p = 0.00) Despite the small mean difference of the mean ICA and PCA, there was no correlation between these two angles. Conclusion. Considering the weak correlation of the FAA and PCA within the group but also individuals, the importance of development of more individual approaches for determining the optimal rotation of the components in total knee surgery is essential. As a result, one should be aware that the widely used, current guidelines for knee rotation of 3 degrees of external rotation in placing total knee arthroplasties shows variation between individuals. A more individual approach in total knee arthroplasty seems essential for future knee prosthesis implantations