Introduction. Leg length and offset are important considerations in total hip arthroplasty (THA). Navigation systems are capable of providing intra-operative measurements of leg length and offset, and high accuracy has been shown in experimental studies. Objective. This in-vivo study assesses the accuracy of an imageless navigation system, with a pin-less femoral array, in measuring offset and leg length changes. Method. A prospective, consecutive series of 24 patients undergoing navigated total hip arthroplasty were included in the study. Intra-operative measurements of leg length and offset were recorded using the navigation system. For each patient pre- and post-operative digital radiographs were scaled and analysed to provide radiographic measurements of change in leg length and offset. Results. Measurements of leg length change made by the navigation system showed a statistically significant correlation with the size of change measured radiographically (R=.77, P < 0.0001). The mean difference between the radiographic and navigational measurement was 0.4 ± 2.8 mm. The navigation system was accurate to within 1 mm of the radiographic measurement in 50% of cases, within 2 mm in 67% of cases, and within 5 mm in 96% of cases. Measurements of offset change by the navigation system also showed a statistically significant correlation with radiographic measurements, however the correlation was less pronounced (R=.47, P=0.02). The mean difference between navigational and radiographic measurements was 1.4 ± 6.4 mm. The navigation system was accurate to within 1 mm of the radiographic measurement in 8% of cases, within 2 mm in 25% of cases, and within 5 mm in 75% of cases. Conclusion. This study demonstrates in-vivo that an imageless, non-invasive navigation system is a reliable tool for intra-operative leg length and offset measurement

In patients with shoulder arthritis, the ability to accurately determine glenoid morphological alterations affects the outcomes of shoulder arthroplasty surgery significantly. This study was conducted to determine whether there is a correlation between scapular and glenoid morphometric components. Existence of such a correlation may help surgeons accurately estimate glenoid bone loss during pre-operative planning.

The dimensions and geometric relationships of the scapula, scapula apophysis and glenoid were assessed using CT scan images of 37 South African and 40 Chinese cadavers. Various anatomical landmarks were marked on the 77 scapulae and a custom script was developed to perform the measurements. Intra-cohort correlation and inter-cohort differences were statistically analysed using IBM SPSS v28. The condition for statistical significance was p<0.05.

The glenoid width and height were found to be significantly (p<0.05) correlated with superior glenoid to acromion tip distance, scapula height, acromion tip to acromion angle distance, acromion width, scapula width, and coracoid width, in both the cohorts. While anterior glenoid to coracoid tip distance was found to be significantly correlated to glenoid height and width in the South African cohort, it was only significantly correlated to glenoid height in the Chinese cohort. Significant (p<0.05) inter-cohort differences were observed for coracoid height, coracoid width, glenoid width, scapula width, superior glenoid to acromion tip distance, and anterior glenoid to coracoid tip distance.

This study found correlations between the scapula apophyseal and glenoid measurements in the population groups studied. These morphometric correlations can be used to estimate the quantity of bone loss in shoulder arthroplasty patients.

The KT1000 is widely accepted as a tool for the instrumented measurement of the anteroposterior tibial translation. The aim of this study is to compare the data obtained with the KT1000 in ACL deficient knees with the data obtained using a navigation system during “in vivo” ACL reconstruction procedures and to validate the accuracy of the KT1000. An ACL reconstruction was performed using computer aided surgical navigation (Orthopilot, B-Braun, A esculap, Tuttlingen, Germany) in thirty patients. Antero-posterior laxity measurements were obtained for all patients using KT1000 arthrometer (in a conscious state and under general anesthesia) and during surgery using the navigation system, always at 30° of knee flexion. The mean AP translation was 14±4 mm and 15,6±3,8 using the KT1000 in conscious and under general anesthesia respectively (p=0.02) and 16,1±3,7 mm using navigation. Measurements with the KT1000 under general anesthesia were not different to those obtained “in vivo” with the navigation system (p=0,37). In conclusion this study validates the accuracy of the KT1000 to exactly calculate AP translation of the tibia, in comparison with the more accurate measurements obtained using a navigation system

3D accurate measurements of the skeletal structures of the foot, in physiological and impaired subjects, are now possible using Cone-Beam CT (CBCT) under real-world loading conditions. In detail, this feature allows a more realistic representation of the relative bone-bone interactions of the foot as they occur under patient-specific body weight conditions. In this context, varus/valgus of the hindfoot under altered conditions or the thinning of plantar tissues that occurs with advancing age are among the most complex and interesting to represent, and numerous measurement proposals have been proposed. This study aims to analyze and compare these measurements from CBCT in weight-bearing scans in a clinical population. Sixteen feet of diabetic patients and ten feet with severe adult flatfoot acquired before/after corrective surgery underwent CBCT scans (Carestream, USA) while standing on the leg of interest. Corresponding 3D shapes of each bone of the shank and hindfoot were reconstructed (Materialise, Belgium). Six different techniques found in the literature were used to calculate the varus/valgus deformity, i.e., the inclination of the hindfoot in the frontal plane of the shank, and the distance between the ground and the metatarsal heads was calculated along with different solutions for the identification of possible calcifications. Starting with an accurate 3D reconstruction of the skeletal structures of the foot, a wide range of measurements representing the same angle of hindfoot alignment were found, some of them very different from each other. Interesting correlations were found between metatarsal height and subject age, significant in diabetic feet for the fourth and fifth metatarsal bones. Finally, CBCT allows 3D assessment of foot deformities under loaded conditions. The observed traditional measurement differences and new measurement solutions suggest that clinicians should consider carefully the anatomical and functional concepts underlying measurement techniques when drawing clinical and surgical conclusions.

This study examined pre-operative measures to predict post-operative biomechanical outcomes in total knee arthroplasty (TKA) patients.

Twenty-eight patients (female=12/male=16, age=63.6±6.9, BMI=29.9±7.4 kg/m2) with knee osteoarthritis scheduled to undergo TKA were included. All surgeries were performed by the same surgeon (GD) with a subvastus approach. Patients visited the gait lab within one-month prior to surgery and 12 months following surgery. At the gait lab, patients completed the knee injury and osteoarthritis outcome score (KOOS), a timed up and go (TUG), maximum knee flexion and extension strength evaluation, and a walking task. Variables of interest included the five KOOS sub-scores, TUG time, maximum knee flexion and extension strength normalized to body weight, walking speed, and peak knee biomechanics variables (flexion angle, abduction moment, power absorption). A Pearson's correlation was used to identify significantly correlated variables which were then inputted into a multiple regression.

No assumption violations for the multiple regression existed for any variables. Pre-operative knee flexion and extension strength, TUG time, and age were used in the multiple regression. The multiple regression model statistically significantly predicted peak knee abduction moment, post-operative walking speed, and post-operative knee flexion strength. All four variables added statistically significantly to the prediction p<.05.

Pre-operative KOOS values did not correlate with any biomechanical indicators of post-operative success. Age, pre-operative knee flexion and extension strength, and TUG times predicted peak knee abduction moment, which is associated with medial knee joint loading. These findings stress the importance of pre-surgery condition, as stronger individuals achieved better post-operative biomechanical outcomes. Additionally, younger patients had better outcomes, suggesting that surgeons should not delay surgery in younger patients. This delay in surgery may prevent patients from achieving optimal outcomes. Future studies should utilize a hierarchical multiple regression to identify which variables are most predictive.

Background

In vivo evaluation of IVD strains is crucial to better understand normal and pathological IVD mechanics, and to evaluate the effectiveness of treatments. This study aimed to 1) develop a novel in vivo technique based on 3T MRI and digital volume correlation (DVC) to measure strains within IVDs and 2) to use this technique to resolve 3D strains within IVDs of healthy volunteers during extension.

Centre Hospitalo-Universitaire de Bordeaux, Service de Pathologie du la Colonne Vertébrale, Bordeaux, France. Assessment of cervical lordosis using a standardised digital acquisition procedure in the normal population. Three independent reviewers measured static lordosis. The EOS¯ system, which utilises low dose radiation and provides reliable standardized digital 2D acquisition with 3D reconstruction was employed. Measurements were carried out twice by every examiner on two different occasions. Cohort of the general public of 180 subjects divided into 4 groups (both sexes individually, age less than 40 and greater than 50 individually). None had any previous history of spinal disorders or sagittal imbalance. General cervical lordosis (C2 to C7) as well as upper and lower cervical lordosis were assessed. Cervical lordosis in the general population has a very wide range in both sexes. Overall cervical lordosis was 37 degrees. Lower cervical lordosis (superior endplate of C4 to inferior endplate of C7) demonstrated an average of 16 degrees, and upper cervical lordosis was found to be 21 degrees. No particular age group or sex was more prone to having lesser/greater lordosis. Current literature is sparse and provides large ranges, different standards and variable methods for assessing standard cervical lordosis. Overall cervical lordosis is very variable amongst the sexes and age groups. We provide a standard set of values which help to provide the spinal surgeon with values to aim for when seeking to restore cervical lordosis

Introduction. The Hamann-Todd collection at the Cleveland Museum of Natural History (Cleveland, OH, USA) includes 63 paediatric skeletal specimens in varying condition and completeness. The initial data collection included representative skeletons of children aged 1–18 years. The aim of this study was to better understand the growth patterns of the paediatricspine and ribs. Methods. Data from vertebrae and corresponding ribs were collected. Data included 46 measurements from the vertebral body and ribs at T1, T4, T7, T10, and L3. Measurements were obtained with Vernier calipers, tape measures, and photographs of each bone. Several specimens were digitised with a Next Engine 3D laser scanner. The initial analysis used caliper-derived data, with some measurements obtained from photographs. The data were analysed by age, specific bone, and morphological features. More than 2000 cross correlations were studied. Linear regressions were done on scalar measurements with SAS (version 9.1.3) and JMP (version 8.0). Although the general demographics for each child were known, specifics such as height and weight or previous trauma were not. Results. Data analysis showed linear relationships in the ribs and growing spine. For example, the figure shows the data and linear regression for the right rib at T7 for each age. Rib width showed no significant increase with age (r2=0·001), whereas rib height had a linear increase (r2=0·754). Other measurements, such as costal length, were highly correlated with age. Conclusions. Direct measurements of paediatric cadaveric bones can be statistically analysed to provide insight into normal human growth. The data show a linear growth of the spine and rib cage from ages 1–18 years. Relatively little is known about the normal growth of human ribs and spine. This is the first known osteological data collection of the growing ribs and spine in non-scoliotic children. Understanding of chest growth will help to improve treatment of spine and chest-wall deformity in growing children

Accurate measurement of pelvic tilt (PT) is critical in diagnosing hip and spine pathologies. Yet a sagittal pelvic radiograph with good quality is not always available. Studies explored the correlation between PT and sacro-femoral-pubic (SFP) angle from anteroposterior (AP) radiographs yet demonstrated conflicting conclusions about its feasibilities. This study aims to perform a cohort-controlled meta-analysis to examine the correlation between the SFP angle and PT and proposes an application range of the method.

This study searched PubMed, Embase, Cochrane, and Web of Science databases for studies that evaluated the correlation between SFP angle and PT. The Pearson's correlation coefficient r from studies were tabulated and compared. Pooled r for overall and gender/age (teenage or adult) controlled subgroup were reported using Fisher's Z transformation. Heterogeneity and publication bias were evaluated using Egger's regression test for the funnel plot asymmetry.

Eleven studies were recruited, with nine reported r (totalling 1,247 patients). The overall pooled r was 0.61 with high inter-study heterogeneity (I2 = 75.95%). Subgroup analysis showed that the adult group had a higher r than the teenage group (0.70 versus 0.56, p < 0.001). Although statistically insignificant (p = 0.062), the female group showed a higher r than the male group (0.72 versus 0.65).

The SFP method must be used with caution and should not be used in the male teenage group. The current studies did not demonstrate that the SFP method was superior to other AP landmarks correlating to PT. Identical heterogeneity was observed among studies, indicating that more ethnicity-segregated and gender-specific subgroup studies might be necessary. More data input analysing the errors will be useful.

Identifying and restoring alignment is a primary aim of total knee arthroplasty (TKA). In the coronal plane, the pre-pathological hip knee angle can be predicted using an arithmetic method (aHKA) by measuring the medial proximal tibial angle (MPTA) and lateral distal femoral angle (aHKA=MPTA - LDFA). The aHKA is shown to be predictive of coronal alignment prior to the onset of osteoarthritis; a useful guide when considering a non-mechanically aligned TKA. The aim of this study is to investigate the intra- and inter-observer accuracy of aHKA measurements on long leg standing radiographs (LLR) and preoperative Mako CT planning scans (CTs).

Sixty-eight patients who underwent TKA from 2020–2021 with pre-operative LLR and CTs were included. Three observers (Surgeon, Fellow, Registrar) measured the LDFA and MPTA on LLR and CT independently on three separate occasions, to determine aHKA. Statistical analysis was undertaken with Bland-Altman test and coefficient of repeatability.

An average intra-observer measurement error of 3.5° on LLR and 1.73° on CTs for MPTA was detected. Inter-observer errors were 2.74° on LLR and 1.28° on CTs. For LDFA, average intra-observer measurement error was 2.93° on LLR and 2.3° on CTs, with inter-observer errors of 2.31° on LLR and 1.92° on CTs. Average aHKA intra-observer error was 4.8° on LLR and 2.82° on CTs. Inter-observer error of 3.56° for LLR and 2.0° on CTs was measured.

The aHKA is reproducible on both LLR and CT. CT measurements are more reproducible both between and within observers. The difference between measurements using LLR and CT is small and hence these two can be considered interchangeable. CT may obviate the need for LLRs and may overcome difficulties associated with positioning, rotation, body habitus and flexion contractures when assessing coronal alignment.

Introduction: (1) Determine whether initial MRI findings correlate with clinical outcome.(2) Study the reproducibility of MRI measurements of large disc prolapses.(3) Estimate the ability to predict CES based on MRI alone.(4) Does CES only occur in degenerate discs?. Method: 31 patients with CES were identified and invited to attend clinic. 19 patients who underwent discectomy were identified. Digital photographs of all 50 MRIs were obtained. Observers: 1 Radiologist, 2 Spinal Surgeons and 1 Trainee did not know the number of patients in each group. Observers estimated the percentage spinal canal compromise on each view (0–100%), indicated whether they thought the scan findings could produce CES and commented on disc degeneration. Measurements were repeated after 2 weeks. Results: 26 patients attended clinic – mean follow up 51 months (range 25–97). 12 of the 26 patients with CES had, on average, > 75% canal compromise. No significant correlations were found between MRI canal compromise and clinical outcome. Kappa values for intra-observer reproducibility of measurements ranged from 0.4–0.85 and inter-observer 0.63–5. Based on MRI, the correct identification of CES has sensitivity 68%, specificity 78%, positive predictive value 84% and negative predictive value 58%. Over 80% of the CES causing discs were degenerate. Discussion: Canal compromise does not appear to predict clinical outcome. MRI measurement reproducibility has substantial agreement. CES is a clinical diagnosis supported by an MRI scan. In less clear cases the presence of a large disc on an MRI scan supports a diagnosis of CES (PPV 84%). CES occurs in degenerate discs

Introduction: Current evidence suggests CES should be operated < 48 hours from onset. MRI scanning is often not available 24 hours a day. Objectives: (1) Determine whether MRI findings correlate with clinical outcome. (2) Study the reproducibility of MRI measurements of large disc prolapses. (3) Estimate the ability to predict CES based on MRI alone. Study Design: 31 CES patients were identified,contactedand invited to follow up. Clinical outcome consisted of history and examination, and validated questionnaire assessments. 19 patients who underwent discectomy were identified. T2 mid-sagittal and axial digital photographs of all 50 MRIs were obtained. Observers did not know the number of patients in each group (1 Consultant Radiologist, 2 Consultant Spinal Surgeons and 1 SHO). They estimated the percentage spinal canal compromise on each view (0–100%) and indicated whether they thought the scan findings could produce CES. Measurements were repeated after 2 weeks. Results: 26 patients attended clinic (mean follow up 51 months). There were no significant correlations found between MRI canal compromise and clinical outcome. Kappa values for the measurements ranged 0.52–0.85 and 0.61–0.75 for intra- and inter-observer reproducibility. Based on MRI alone correct identification of CES has sensitivity 67%, specificity 81%, positive predictive value 85% and negative predictive value 60%. Conclusions: Canal compromise on MRI does not predict the outcome of patients with CES. Reproducibility of MRI measurements of large disc protrusions has substantial agreement. MRI could be of help in equivocal cases if the scan shows a large disc

Wear and loosening are the major causes for long tem failure in Total Hip Replacement (THR). Accurate three dimensional wear analysis of radiographs has its own limitations. We report the results of our clinical study of three dimensional volumetric wear measurements using our custom low radiation risk CT based algorithm and special software. Twenty four patients (32 hips) agreed to take part in our study. The male: female ratio was 1:4. The mean age was 75 years and the mean follow up was 5.4 years. All patients had 28 mm diameter ceramic heads. Of the 32 hips, 17 hips had polyethylene inserts and 15 hips had ceramic inserts. The maximum follow up for the polyethylene and ceramic groups were 12 years and 5.5 years respectively. All the patients were scanned using Somatom Sensation 4 scanner. Using custom software, 3D reconstruction of the components was done and landmark acquisition done on the femoral head, acetabular metal component and the insert. From these landmarks, a dedicated program was used to calculate the centre of the femoral head in relation to the centre of the acetabular component in all three axes and an indirect measurement of wear obtained. Using the axes measurements graphical 3D models of migration of the femoral head component into the acetabular liner were created and volume of wear measured using special software. Accuracy of the method was assessed by measuring the radius of the femoral head since all patients had 28mm diameter heads implanted in them. Assessment of precision of method was done by calculating the level of agreement between two independent observers. In the polyethylene group, there was no significant (< 1mm) wear in x and y axis with time. However there was significant evidence of wear in relation to time in the z axis (max wear = −2.5 mm). In the ceramic group with relatively shorter follow up, there was no evidence of significant wear in all three axes. The mean volume measured in the polyethylene group was 685 mm3 (max = 1629 mm3, min = 132mm3 ). The mean volume measured in the ceramic group was 350mm3 (max = 1045 mm3, min = 139mm3 ). The mean radius of the femoral head measured in both groups was 14.02mm (range =13.8 to 14.4 mm). Accuracy was limited by artifacts particularly in bilateral hip arthroplasties and further in the ceramic group because of the restricted access to the ceramic head for placement of markers. Measurements obtained by two independent observers showed a strong correlation (0.99, p value = 0.001) for the polyethylene group. In the ceramic group the correlation (0.69, p value=0.0126) was not as strong as the polyethylene group. This study has produced a method for three dimensional estimation of wear that can be obtained from low dose CT scans with better accuracy and repeatability (< 0.5 mm) even than to ex vivo studies particularly in polyethylene bearings(wear rate 0.14mm/yr). Noise reduction with appropriate artefact reduction software may further improve the accuracy of this simple and repeatable method

Acute Compartment Syndrome (ACS) is an orthopaedic emergency that can develop after a wide array of etiologies. In this pilot study the MY01 device was used to assess its ease of use and its ability to continuously reflect the intracompartmental pressure (ICP) and transmit this data to a mobile device in real time. This preliminary data is from the lead site which is presently expanding data collection to five other sites as part of a multi-center study.

Patients with long bone trauma of the lower or upper extremity posing a possibility of developing compartment syndrome were enrolled in the study. Informed consent was obtained from the patients. A Health Canada licensed continuous compartmental pressure monitor (MY01) was used to measure ICP. The device was inserted in the compartment that was deemed most likely to develop ACS and ICP was continuously measured for up to 18 hours. Fractures were classified according to the AO/OTA classification. Patient clinical signs and pain levels were recorded by healthcare staff during routine in-patient monitoring and were compared to the ICP from the device. Important treatment information was pulled from the patient's chart to help correlate all of the patient's data and symptoms.

The study period was conducted from November 2020 through December 2021. Twenty-six patients were enrolled. There were 17 males, and nine females. The mean age was 38 years (range, 17–76). Seventeen patients received the device post-operatively and nine received it pre-operatively. Preliminary results show that post-operative ICPs tend to be significantly higher than pre-operative ICPs but tend to trend downwards very quickly. The trend in this measurement appears to be more significant than absolute numbers which is a real change from the previous literature. One patient pre-operatively illustrated a steep trend upwards with minimal clinical symptoms but required compartment release at the time of surgery that exhibited no muscle necrosis. The trend in this patient was very steep and, as predicted, predated the clinical findings of compartment syndrome. This trend allows an early warning signal of the absolute pressure, to come, in the compartment that is being assessed by the device.

Preliminary results suggest that this device is reliable and relatively easy to use within our institutions. In addition it suggests that intracompartmental pressures can be higher immediately post-op but lower rapidly when the patient does not develop ACS. These results are in line with current literature of the difference between pre and post-operative baselines and thresholds of ICP, but are much more striking, as continuous measurements have not been part of the data set in most of past studies.

Further elucidation of the pressure thresholds and profiles are currently being studied in the ongoing larger multicenter study and will add to our understanding of the critical values. This data, plus the added value of continuous trends in the pressure, upwards or downwards, will aid in preventing muscle necrosis during our management of these difficult long bone fractures.

Introduction: Current evidence suggests that CES should be operated within 48 hours from onset of sphincteric symptoms in order to maximise chances of recovery. Measurement reproducibility of large disc prolapses and clinical correlations have not previously been studied. Objectives: (1) Determine whether initial MRI findings correlate with clinical outcome (2) Study the reproducibility of MRI measurements of large disc prolapses (3) Estimate the ability to predict CES based on MRI alone. Study Design: 31 patients with CES were identified, the case notes reviewed and the patients invited to attend clinic. Outcome consisted of history and examination, and several validated questionnaire assessments. 19 patients who underwent discectomy for persistent radiculopathy were identified. None had sphincteric symptoms. All had a significant surgical target. Digital photographs of all 50 MRIs were obtained showing the T2 mid-sagittal image and the axial image with the greatest disc protrusion. The Observers: 1 Consultant Radiologist, 2 Consultant Spinal Surgeons and 1 SHO did not know the number of patients in each group. Observers estimated the percentage spinal canal compromise on each view and indicated whether they thought the scan findings could produce CES. Measurements were repeated after 2 weeks. Results: 26 patients attended clinic mean follow up 51 months (25 to 97). As expected, the % canal compromise differed significantly between the two groups (p0.001). 12 of the 26 patients with CES had, on average, over75% canal compromise. No significant correlations were found between MRI canal compromise and clinical outcome. Canal compromise did predict whether the patient would fail their Trial Without Catheter (p0.05). Based on MRI alone, the correct identification of CES has sensitivity 68%, specificity 78%, positive predictive value 84% and negative predictive value 58%. Kappa values for intra-observer reproducibility ranged from 0.4 to 0.85 for sagittal compromise, axial compromise and correct prediction of CES. All three interobserver kappa values for these measurements were 0.64. Conclusions: This is the largest radiological case series of CES with 4 years clinical follow up. Canal compromise on MRI does not appear to directly predict clinical outcome. Reproducibility of MRI measurements of large disc protrusions has substantial agreement. MRI could be of help in equivocal cases if the scan shows a large disc

We aimed (1) to determine the factors which influence outcome after surgery for CES and (2) to study CES MRI measurements. 56 patients with evidence of a sphincteric disturbance who underwent urgent surgery (1994-2002) were identified and invited to clinic. 31 MRIs were available for analysis and randomised with 19 MRIs of patients undergoing discectomy for persistent radiculopathy. Observers estimated the percentage of spinal canal compromise and indicated whether they thought the scan findings could produce CES and whether the discs looked degenerate. Measurements were repeated after two weeks. (1) 42 patients attended (mean follow up 60 months; range 25–114). Mean age at onset was 41 years (range 24–67). 26 patients were operated on within 48 hours of onset. Acute onset of sphincteric symptoms and the time to operation did not influence the outcomes. Leg weakness at onset persisted in a significant number at follow-up (p<0.005). Bowel disturbance at presentation was associated with sexual problems (<0.005) at follow-up. Urinary disturbance at presentation did not affect the outcomes. The 13 patients who failed their post-operative trial without catheter had worse outcomes. The SF36 scores at follow-up were reduced compared to age-matched norms in the population. The mean ODI was 29, LBOS 42 and VAS 4.5. (2) No significant correlations were found between MRI canal compromise and clinical outcome. There was moderate to substantial agreement for intra- and inter-observer reproducibility. Conclusions. Due to small numbers we cannot make the conclusion that delay to surgery influences outcome. Based on the SF36, LBOS and ODI scores, patients who have had CES do not return to a normal status. Using MRI alone, the correct identification of CES has sensitivity 68%, specificity 80% positive predictive value 84% and negative predictive value 60%. CES occurs in degenerate discs

Introduction: We state that preserving the hip might be optimum in treatment of patients with dislocated femoral fractures presuming that the fractures unite. In order to be able to choose the right treatment for the patient with a dislocated femoral neck fracture, we have hypothesized that lack of blood flow and development of ischemia might have influence on outcome of the osteosynthesis. In this study we have established microdialysis and laser Doppler measurements in patients with a dislocated femoral neck fractures. Methods and materials: 14 patients with dislocated fractures of the femoral neck were osteosynthezised by using 2 cannulated screws. During the operation blood flow was measured with laser Doppler in order to detect pulsatile flow, and microdialysis was performed to detect ischemia. Both measurements were made in the femoral head and with the greater trochanter as control. The parameters measured were lactate, pyruvate, glycerol and glucose concentrations. Lactate/pyruvate ratio was calculated in order to estimate ischemia defined as a value over 25. Measurements were done after the fracture was reduced, and during osteosynthesis. Data are presented as mean with standard deviation (SD) in brackets. Results: In all but one patient laser Doppler showed pulsatile flow in the greater trochanter, whereas 8 patients had flow in the femoral head. In the greater trochanter the mean lactate/pyruvate ratio was 11 (7.55), in the femoral heads the mean ratio was 27.99 (21.24) although 4 heads did not show ischemia (p=0.0004). The values for glucose in the trochanter and the femoral head are 2.47 mM(1.92) and 1.53 mM(1.37) respectively, and for glycerol 0.16 mM(0.09) and 0.25 mM(0.22). During the observation period two patients were reoperated, one with hemiarthroplasty 3 months after the osteosynthesis due to failure of the osteosynthesis; the patient had flow measured by laser Doppler and ischemia with microdialysis. One had a resection arthroplasty due to infection. Conclusion: To our knowledge it is the first time that laser Doppler and microdialysis has been established in patients with dislocated femoral neck fractures. Further studies will have to evaluate whether laser Doppler and microdialysis in combination with fracture related parameters can predict failure of the osteosynthesis. This might enable us to establish a treatment algorithm to be used in the daily clinic

Abstract

Introduction: Measurements taken from digital radiographs and corrected for the labelled scale do not correspond to actual clinical dimensions accurately. Methods: The routine radiographs taken of 30 hip hemi-arthoplasty patients were used to make measurements in the region of the hip. 15 patients were compared in two hospitals using different digital imaging processing. The images were scaled to 100% (actual size), three blinded measurements were taken of the prosthetic femoral head and the average calculated. These results were compared to the actual size of the implanted prosthesis. Further analysis was carried out to determine true magnification. Results: A consistent difference was observed between measured dimensions at 100% scale and known actual prosthesis dimensions. It was identified that the magnification factor ranged from 110 to 115% with at average magnification factor of 113%. No significant difference was observed between the two hospital systems. Discussion: Many factors influence radiographic magnification, including variations in distances from x-ray source to patient and from x-ray source to x-ray plate. Angulation and degree of divergence of the x-ray beam and rotation of a limb also influence the magnification which occurs. Accurate measurements can only be taken from digital x-rays if appropriate calibration is performed

Abstract