Are there functional biomechanical differences in robotic arm-assisted bi-unicompartmental knee arthroplasty compared with conventional total knee arthroplasty? A prospective, randomized controlled trial

AIMS

The aim of this study was to compare any differences in the primary outcome (biphasic flexion knee moment during gait) of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) at one year post-surgery.

METHODS

A total of 76 patients (34 bi-UKA and 42 TKA patients) were analyzed in a prospective, single-centre, randomized controlled trial. Flat ground shod gait analysis was performed preoperatively and one year postoperatively. Knee flexion moment was calculated from motion capture markers and force plates. The same setup determined proprioception outcomes during a joint position sense test and one-leg standing. Surgery allocation, surgeon, and secondary outcomes were analyzed for prediction of the primary outcome from a binary regression model.

RESULTS

Both interventions were shown to be effective treatment options, with no significant differences shown between interventions for the primary outcome of this study (18/35 (51.4%) biphasic TKA patients vs 20/31 (64.5%) biphasic bi-UKA patients; p = 0.558). All outcomes were compared to an age-matched, healthy cohort that outperformed both groups, indicating residual deficits exists following surgery. Logistic regression analysis of primary outcome with secondary outcomes indicated that the most significant predictor of postoperative biphasic knee moments was preoperative knee moment profile and trochlear degradation (Outerbridge) (R² = 0.381; p = 0.002, p = 0.046). A separate regression of alignment against primary outcome indicated significant bi-UKA femoral and tibial axial alignment (R² = 0.352; p = 0.029), and TKA femoral sagittal alignment (R² = 0.252; p = 0.016). The bi-UKA group showed a significant increased ability in the proprioceptive joint position test, but no difference was found in more dynamic testing of proprioception.

CONCLUSION

Robotic arm-assisted bi-UKA demonstrated equivalence to TKA in achieving a biphasic gait pattern after surgery for osteoarthritis of the knee. Both treatments are successful at improving gait, but both leave the patients with a functional limitation that is not present in healthy age-matched controls. Cite this article: Bone Joint J 2022;103-B(4):433-443.

Early outcomes after robotic arm-assisted bi-unicompartmental knee arthroplasty compared with total knee arthroplasty: a prospective, randomized controlled trial

AIMS

The aim of this study was to compare the clinical outcomes of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) during the first six weeks and at one year postoperatively.

METHODS

A per protocol analysis of 76 patients, 43 of whom underwent TKA and 34 of whom underwent bi-UKA, was performed from a prospective, single-centre, randomized controlled trial. Diaries kept by the patients recorded pain, function, and the use of analgesics daily throughout the first week and weekly between the second and sixth weeks. Patient-reported outcome measures (PROMs) were compared preoperatively, and at three months and one year postoperatively. Data were also compared longitudinally and a subgroup analysis was conducted, stratified by preoperative PROM status.

RESULTS

Both operations were shown to offer comparable outcomes, with no significant differences between the groups across all timepoints and outcome measures. Both groups also had similarly low rates of complications. Subgroup analysis for preoperative psychological state, activity levels, and BMI showed no difference in outcomes between the two groups.

CONCLUSION

Robotic arm-assisted, cruciate-sparing bi-UKA offered similar early clinical outcomes and rates of complications to a mechanically aligned TKA, both in the immediate postoperative period and up to one year following surgery. Further work is required to identify which patients with osteoarthritis of the knee will derive benefit from a cruciate-sparing bi-UKA. Cite this article: Bone Joint J 2021;103-B(10):1561-1570.

Robotic arm-assisted bi-unicompartmental knee arthroplasty maintains natural knee joint anatomy compared with total knee arthroplasty: a prospective randomized controlled trial

AIMS

The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and alignment of the lower limb following surgery.

METHODS

An analysis of 38 patients who underwent TKA and 32 who underwent bi-UKA was performed as a secondary study from a prospective, single-centre, randomized controlled trial. CT imaging was used to measure coronal, sagittal, and axial alignment of the knee preoperatively and at three months postoperatively to determine changes in anatomy that had occurred as a result of the surgery. The hip-knee-ankle angle (HKAA) was also measured to identify any differences between the two groups.

RESULTS

The pre- to postoperative changes in joint anatomy were significantly less in patients undergoing bi-UKA in all three planes in both the femur and tibia, except for femoral sagittal component orientation in which there was no difference. Overall, for the six parameters of alignment (three femoral and three tibial), 47% of bi-UKAs and 24% TKAs had a change of < 2° (p = 0.045). The change in HKAA towards neutral in varus and valgus knees was significantly less in patients undergoing bi-UKA compared with those undergoing TKA (p < 0.001). Alignment was neutral in those undergoing TKA (mean 179.5° (SD 3.2°)) while those undergoing bi-UKA had mild residual varus or valgus alignment (mean 177.8° (SD 3.4°)) (p < 0.001).

CONCLUSION

Robotic-assisted, cruciate-sparing bi-UKA maintains the natural anatomy of the knee in the coronal, sagittal, and axial planes better, and may therefore preserve normal joint kinematics, compared with a mechanically aligned TKA. This includes preservation of coronal joint line obliquity. HKAA alignment was corrected towards neutral significantly less in patients undergoing bi-UKA, which may represent restoration of the pre-disease constitutional alignment (p < 0.001). Cite this article: Bone Joint J 2020;102-B(11):1511-1518.

The Scottish national LifeCurve™ survey: costs of functional decline, opportunities to achieve early intervention to support well-being in later life, and meaningfulness of the LifeCurve™

OBJECTIVES

The aim of the Scottish AHP LifeCurve™ survey was to gather a snapshot of where people are on their LifeCurve™ when receiving allied health professions (AHP) services and to understand the cost consequence of intervening 'late' in the ageing trajectory. The objectives were to promote discussion around preventing functional decline, support innovation in service delivery, and facilitate broader engagement with individuals, communities, and wider environments for improving health and well-being in later life. In addition, subsequent learning could help address the increasing resource gap between the demand and capacity across health and social care.

STUDY DESIGN

The survey was paper-based in the form of a printed booklet, which contained the 15 activities of daily living (ADL) and instrumental ADL (IADL) which comprise the LifeCurve™ with additional lifestyle questions and information about the member of staff and service the participant was seen in, including their Community Health Index (CHI) number. The survey questions and booklet layout were tested over a five-month period with AHPs and people receiving AHP services. Liaison with national health literacy colleagues and lead speech and language therapists ensured that the survey material was accessible to a wide range of people. In addition, the survey could be made available in alternative formats, on request.

METHODS

Agreement to undertake the national survey was obtained in November 2016 by all AHP directors and associate directors who appointed communication support leads in their area who would support implementation at all stages at a local level. All materials relating to the survey were published on a dedicated area of a community of practice to support awareness and training during the preimplementation phase. AHPs working in adult services were asked to complete a survey with a minimum of two people they would 'typically' see in their service during a two-week period in May 2017, with the exclusion of people who were too unwell to participate, children and young people under 16 years, and adults with incapacity and without a guardianship arrangement in place. Approval was gained from the Public Benefit Privacy Panel to link the survey data to participants' health service usage using their CHI number. Completed forms were returned to the University of Strathclyde for entry into an encrypted electronic database using a double data entry process and were allocated a unique identifier. The unique identifier and CHI numbers were sent to Information Services Division (ISD), and then, the CHI numbers were deleted from the encrypted database. ISD sent the linked health data to the Scottish Government Analytical Services Division, which thus produced a full encrypted and anonymised database.

RESULTS

The data explain what stages on the LifeCurve™ AHPs are intervening, and the matched data provide associated healthcare costs at each stage. Due to poor or missing data in the AHP/Service section, only 60% (n = 8261) of the total completed surveys were able to be matched with health service usage records. These data show that whilst AHPs are seeing people at each of the 15 ADL/IADL stages on the LifeCurve™, interventions fell into three groups where 25% of people where seen at the 'precurve' stage, 13% of people at 'mid-curve' (stage number five), and 39% of people at 'late-curve' (stages 10 to 13). The healthcare cost usage of these participants increased the further along the LifeCurve™ a person moves, with an average annual cost of £2700 at 'precurve' rising to £12,330 at 'late-curve' in 2016-2017. The results indicate that different services and professions are represented at each of these three points. So, for example, as might be expected, outpatient (especially musculoskeletal) services were seen more often at the 'precurve' stage, and in-patient and community rehabilitation, services were seen more often at the 'late-curve' stages; diagnostic radiographers and orthoptists saw people at the 'early-curve' stages, dieticians and podiatrists saw people at the 'mid-curve' stage, whilst physiotherapists, speech and language therapists, and occupational therapists saw people at the 'late-curve' stages. Data analysis showed this pattern is different for people receiving mental health services and, so, their data were removed and will be analysed and reported separately.

CONCLUSIONS

It is clear from the results that healthcare costs increased as participants moved down LifeCurve™ stages, that is, as their levels of functional decline increase. It is also clear that AHPs are intervening late in a person's functional decline with associated limitations on changing their ageing trajectory. The cost consequence of this is significant - moving someone from 'late- to mid-curve' could save £3200 per person per annum. However, those AHPs typically associated with reabling approaches and rehabilitation, which have greatest potential to change ageing trajectories, were not represented at the 'mid-curve' stage (e.g., physiotherapists, occupational therapists). Therefore, we must find places to have conversations with people to inform them that functional decline is malleable and not inevitable purely by virtue of chronological age and provide education and support to prevent or reverse functional decline and collaborate around strategic planning and commissioning to offer different options that support an optimum LifeCurve™.

Robotic-Arm-Assisted vs Conventional Unicompartmental Knee Arthroplasty. The 2-Year Clinical Outcomes of a Randomized Controlled Trial

BACKGROUND

Unicompartmental knee arthroplasty (UKA) for treatment of medial compartment osteoarthritis has potential benefits over total knee arthroplasty but UKA has a higher revision rate. Robotic-assisted UKA is increasingly common and offers more accurate implant positioning and limb alignment, lower early postoperative pain but evidence of functional outcome is lacking. The aim was to assess the clinical outcomes of a single-centre, prospective, randomised controlled trial, comparing robotic-arm-assisted UKA with conventional surgery.

METHODS

A total of 139 participants were recruited and underwent robotic-arm-assisted (fixed bearing) or conventional (mobile bearing) UKA. Fifty-eight patients in the robotic-arm-assisted group and 54 in the manual group at 2 years. The main outcome measures were the Oxford Knee Score, American Knee Society Score and revision rate.

RESULTS

At 2 years, there were no significant differences for any of the outcome measures. Sub-group analysis (n = 35) of participants with a preoperative University of California Los Angeles Activity Scale >5 (more active) was performed. In this sub-group, the median Oxford Knee Score at 2 years was 46 (IQR 42.0-48.0) for robotic-arm-assisted and 41 (IQR 38.5-44.0) for the manual group (P = .036). The median American Knee Society Score was 193.5 (IQR 184.0-198.0) for the robotic-arm-assisted group and 174.0 (IQR 166.0-188.5) for the manual group (P = .017). Survivorship was 100% in robotic-arm-assisted group and 96.3% in the manual group.

CONCLUSION

Overall, participants achieved an outcome equivalent to the most widely implanted UKA in the United Kingdom. Sub-group analysis suggests that more active patients may benefit from robotic-arm- assisted surgery. Long term follow-up is required to evaluate differences in survivorship.

A novel approach for intra-operative shape acquisition of the tibio-femoral joints using 3D laser scanning in computer assisted orthopaedic surgery

BACKGROUND

Image registration (IR) is an important process of developing a spatial relationship between pre-operative data and the physical patient in the operation theatre. Current IR techniques for Computer Assisted Orthopaedic Surgery (CAOS) are time consuming and costly. There is a need to automate and accelerate this process.

METHODS

Bespoke quick, cost effective, contactless and automated 3D laser scanning techniques based on the DAVID Laserscanner method were designed. 10 cadaveric knee joints were intra-operatively laser scanned and were registered with the pre-operative MRI scans. The results are supported with a concurrent validity study.

RESULTS

The average absolute errors between scan models were systematically less than 1 mm. Errors on femoral surfaces were higher than tibial surfaces (P<0.05). Additionally, scans acquired through the large exposure produced higher errors than the smaller exposure (P<0.05).

CONCLUSION

This study has provided proof of concept for a novel automated shape acquisition and registration technique for CAOS.

Thermal Damage Done to Bone by Burring and Sawing With and Without Irrigation in Knee Arthroplasty

BACKGROUND

Heat from bone resecting tools used in knee surgery can induce thermal osteonecrosis, potentially causing aseptic implant loosening. This study compared oscillating saws to burrs in terms of temperature generation and histologic damage. Use of irrigation to reduce bone temperature was also investigated.

METHODS

Temperatures were recorded during sawing and burring with or without irrigation (uncooled or cooled). Histologic analyses were then carried out. Differences between groups were tested statistically (α = 0.05).

RESULTS

On average, burring produced higher temperatures than sawing (P < .001). When uncooled irrigation was used, bone temperatures were significantly lower in sawed bone than in burred bone (P < .001). Irrigation lowered temperatures and thermal damage depths and increased osteocyte viability (P < .001).

CONCLUSION

These results suggest that irrigating bone during resection could prevent osteonecrosis onset.

Does stroke location predict walk speed response to gait rehabilitation?

OBJECTIVES

Recovery of independent ambulation after stroke is a major goal. However, which rehabilitation regimen best benefits each individual is unknown and decisions are currently made on a subjective basis. Predictors of response to specific therapies would guide the type of therapy most appropriate for each patient. Although lesion topography is a strong predictor of upper limb response, walking involves more distributed functions. Earlier studies that assessed the cortico-spinal tract (CST) were negative, suggesting other structures may be important.

EXPERIMENTAL DESIGN

The relationship between lesion topography and response of walking speed to standard rehabilitation was assessed in 50 adult-onset patients using both volumetric measurement of CST lesion load and voxel-based lesion-symptom mapping (VLSM) to assess non-CST structures. Two functional mobility scales, the functional ambulation category (FAC) and the modified rivermead mobility index (MRMI) were also administered. Performance measures were obtained both at entry into the study (3-42 days post-stroke) and at the end of a 6-week course of therapy. Baseline score, age, time since stroke onset and white matter hyperintensities score were included as nuisance covariates in regression models.

PRINCIPAL OBSERVATIONS

CST damage independently predicted response to therapy for FAC and MRMI, but not for walk speed. However, using VLSM the latter was predicted by damage to the putamen, insula, external capsule and neighbouring white matter.

CONCLUSIONS

Walk speed response to rehabilitation was affected by damage involving the putamen and neighbouring structures but not the CST, while the latter had modest but significant impact on everyday functions of general mobility and gait. Hum Brain Mapp 37:689-703, 2016. © 2015 Wiley Periodicals, Inc.

Tensile properties of the transverse carpal ligament and carpal tunnel complex

BACKGROUND

A new sophisticated method that uses video analysis techniques together with a Maillon Rapide Delta to determine the tensile properties of the transverse carpal ligament-carpal tunnel complex has been developed.

METHODS

Six embalmed cadaveric specimens amputated at the mid-forearm and aged (mean (SD)): 82 (6.29) years were tested. The six hands were from three males (four hands) and one female (two hands). Using trigonometry and geometry the elongation and strain of the transverse carpal ligament and carpal arch were calculated. The cross-sectional area of the transverse carpal ligament was determined. Tensile properties of the transverse carpal ligament-carpal tunnel complex and Load-Displacement data were also obtained. Descriptive statistics, one-way ANOVA together with a post-hoc analysis (Tukey) and t-tests were incorporated.

FINDINGS

A transverse carpal ligament-carpal tunnel complex novel testing method has been developed. The results suggest that there were no significant differences between the original transverse carpal ligament width and transverse carpal ligament at peak elongation (P=0.108). There were significant differences between the original carpal arch width and carpal arch width at peak elongation (P=0.002). The transverse carpal ligament failed either at the mid-substance or at their bony attachments. At maximum deformation the peak load and maximum transverse carpal ligament displacements ranged from 285.74N to 1369.66N and 7.09mm to 18.55mm respectively. The transverse carpal ligament cross-sectional area mean (SD) was 27.21 (3.41)mm(2).

INTERPRETATION

Using this method the results provide useful biomechanical information and data about the tensile properties of the transverse carpal ligament-carpal tunnel complex.

Electromagnetic navigation in total knee arthroplasty-a single center, randomized, single-blind study comparing the results with conventional techniques

We report on the results of a randomized study (n=200) to compare total knee arthroplasty performed using conventional instrumentation or electromagnetic computer assisted surgical technique. 92% of navigated and 85% of conventional knees were implanted within ±3° from neutral mechanical alignment; there was no statistically significant difference between these proportions. There was also no difference in femoral or tibial rotation assessed by CT scan. At 1year follow up there was no statistical difference between the two groups in American Knee Society Score, Oxford Knee Scores, patient satisfaction, quality of life, hospital length of stay, complication rates or other adverse events. Tourniquet time in the navigated group was longer. Proving value for navigation in total knee arthroplasty surgery remains a challenge.

Research synthesis of recommended acetabular cup orientations for total hip arthroplasty

Total hip arthroplasty (THA) is regarded as one of the most successful surgical procedures of modern times yet continues to be associated with a small but significant complication rate. Many early failures may be associated with poor component positioning with, in particular, acetabular component orientation dependent on the subjective judgement of the surgeon. In this paper, we compare the manufacturers' instructions on acetabular cup orientation with the literature-based recommended safety zones and surgical technique, by transforming them onto a single, clinically-relevant framework in which the different reference systems, safety guidelines and current instrumentation surgical techniques can be evaluated. The observed limited consensus between results reflects ongoing uncertainty regarding the optimum acetabular component positioning. As malpositioning of the acetabular cup increases the risk of revision surgery, any ambiguity over the correct position can have a causal effect. Our analysis highlights the need for a surgical reference system which can be used to describe the position of the acetabular cup intra-operatively.

Accuracy of a freehand sculpting tool for unicondylar knee replacement

BACKGROUND

Unicondylar knee replacement is technically challenging and malalignment of the implant components is one of the factors that results in high failure rates. Surgical robotics with navigation is emerging as a potential solution to improve the accuracy of implant placement.

METHODS

The accuracy of performing unicondylar knee replacement using a freehand sculpting, semi-active robotic tool was investigated using 20 synthetic femurs and tibia. Resultant femoral and tibial implant placement was compared to the planned implant position.

RESULTS

The maximum rotational error was 3.2(o) and RMS angular error was 1.46(o) across all orientations, for both the tibia and femoral implants. The maximum translational error was 1.18 mm and the RMS translational error across all directions was 0.61 mm.

CONCLUSIONS

The freehand sculpting tool produced accurate implant placement with small errors comparable to those reported by other robotic-assistive devices on the market for unicondylar knee replacement.

The evaluation of an inexpensive, 2D, video based gait assessment system for clinical use

The purpose of this study was to investigate the clinical potential of an augmented-video-based-portable-system (AVPS). The AVPS included a walkway grid mat made of vinyl flooring, flat paper bull's eye markers, four photoswitches mounted on tripods, a light-indicator, a video camera, and a computer with ProTrainer System software. The AVPS output was compared to a "gold standard" 3D Vicon Motion Analysis System both statically and dynamically over a fixed range (-90° to +90°) using a two-segment-goniometric-rig marked with both bull's eye and retroreflective markers. At each segment angle position, three trials of data were captured. The reliability of the AVPS was also tested using three raters. Further twelve, young, healthy subjects participated in a concurrent validity study in which they performed six gait trials which were simultaneously recorded by both systems. Both motion analysis systems showed low levels of intra subject variability in all kinematic variables indicated by the size of the standard deviations across the six trials. There were no significant differences between the motion systems with respect to the kinematic variables (P>0.05). The results showed a high intra- and inter-rater reliability for both the kinematic and temporo-spatial parameters. With respect to gait events the lowest ICC value for the intra-rater reliability test was 0.993 for the kinematic variables, and ranged from 0.941 to 0.956 for the temporo-spatial variables and 0.731 to 0.954 for the tibia inclination angles. The validation data suggest the AVPS is capable of generating highly reliable and repeatable data when applied to normal subjects and could be used within the clinical setting.

Measuring movement fluency during the sit-to-walk task

BACKGROUND

Restoring movement fluency is a key focus for physical rehabilitation; it's measurement, however, lacks objectivity. The purpose of this study was to find whether measurable movement fluency variables differed between groups of adults with different movement abilities whilst performing the sit-to-walk (STW) movement. The movement fluency variables were: (1) hesitation during movement (reduction in forward velocity of the centre of mass; CoM), (2) coordination (percentage of temporal overlap of joint rotations) and (3) smoothness (number of inflections in the CoM jerk signal).

METHODS

Kinematic data previously collected for another study were extracted for three groups: older adults (n=18), older adults at risk of falling (OARF, n=18), and younger adults (n=20). Each subject performed the STW movement freely while a motion analysis system tracked 11 body segments. The fluency variables were derived from the processed kinematic data and tested for group variation using analysis of variance.

FINDINGS

All three variables showed statistically significant differences among the groups. Hesitation (F=15.11, p<0.001) was greatest in the OARF 47.5% (SD 18.0), compared to older adults 30.3% (SD 15.9) and younger adults 20.8% (SD 11.4). Co-ordination (F=44.88, p<0.001) was lowest for the OARF (6.93%, SD 10.99) compared to both the young (31.21%, SD 5.48) and old (26.24%, SD 5.84). Smoothness (F=35.96, p<0.001) was best in the younger adults, 18.3 (SD 5.2) inflections, compared to the old, 42.5 (SD 11.5) and OARF, 44.25 (SD 7.29).

INTERPRETATION

Hesitation, co-ordination and smoothness may be valid indicators of movement fluency in adults, with important consequences for research and clinical practice.

Developing visualisation software for rehabilitation: investigating the requirements of patients, therapists and the rehabilitation process

This article describes the ongoing process of engaging with users in the development and evaluation of prototype visualisation software, which aims to assist in the understanding and improvement of appropriate movements during rehabilitation. The value of the process is illustrated in the article with a discussion of the key findings of pre-pilot focus groups with stroke survivors and therapists. The article describes how the design of the visualisation software is being adapted to meet the emerging understanding of the needs of patients and professionals, and of the rehabilitation process.

The effect of electromagnetic navigation in total knee arthroplasty on knee kinematics during functional activities using flexible electrogoniometry

BACKGROUND

Navigated total knee arthroplasty has been shown to increase accuracy in post operative implant alignment. By contrast navigated total knee arthroplasty has not shown significant functional improvements to date, when compared with conventional surgery using subjective clinical questionnaire scores. The aim of this study was to compare the knee joint kinematics measured during functional activities using electrogoniometry 12 months after total knee arthroplasty in randomised navigated and conventional total knee arthroplasty groups.

METHODS

The study design was a double blinded, randomised, prospective, controlled trial. The patients were randomised into 2 surgical groups (n=102 navigated group, n=98 conventional group; mean age navigated=67, conventional=67). Flexible electrogoniometry was used to measure patient's knee kinematics with respect to time during 12 functional activities.

FINDINGS

No significant difference was found in terms of the maximum, minimum and excursion knee joint angle during any of the functional activities. However there was a statistically significant improvement in the level and slope gait cycle at the pre swing phase in the navigated group.

INTERPRETATION

There were minimal functional improvements in the navigated total knee arthroplasty group 12 months after surgery. However, these are unlikely to have a significant effect on daily activity for the navigated group.

A purpose-built dynamometer to objectively measure static and dynamic knee torque

This paper reports the development of a purpose-built knee dynamometer (PBKD) to evaluate passive range of motion (ROM) and isometric muscle strength measurements of the knee. The PBKD uses a TorqSense rotary torque transducer and objectively measures isometric knee muscle strength in a valid and reliable manner and passive resistance to motion through range. The device and all associated instrumentation underwent dynamic and static calibration to ensure consistent and accurate measurements were obtained in terms of knee joint angular position, passive torque measures, and isometric torque measures. Eleven healthy male participants performed a knee flexion and extension task designed to evaluate knee function. The validation of the PBKD entailed measuring the consistency of measurement and accuracy of measurement. Accuracy of the PBKD was determined by comparing peak isometric muscle strength measurements against a KIN-COM machine. No significant differences were observed both passively and isometrically between cycles and between trials. This device can have widespread applications within the rehabilitation and clinical environment and could be used as a functional outcome measuring tool to distinguish pathological from non-pathological knees. The presented preliminary results indicate that reliable and accurate measurements of knee ROM and muscle strength can be obtained.

Gait kinematics and passive knee joint range of motion in children with hypermobility syndrome

Hypermobility syndrome (HMS) is characterised by generalised joint laxity and musculoskeletal complaints. Gait abnormalities have been reported in children with HMS but have not been empirically investigated. The extent of passive knee joint range of motion (ROM) has also not been well reported in children with HMS. This study evaluated gait kinematics and passive knee joint ROM in children diagnosed with HMS and healthy controls. Thirty-seven healthy children (mean age±SD=11.5±2.6 years) and 29 children with HMS (mean age±SD=11.9±1.8 years) participated. Sagittal knee motion and gait speed were evaluated using a VICON 3D motion analysis system. Passive knee ROM was measured with a manual goniometer. Independent t-tests compared the values of sagittal knee motion and gait speed between the two groups. Mann-Whitney U tests compared passive knee ROM between groups. Passive ROM (extension and flexion) was significantly higher (both p<0.001) in children with HMS than the healthy controls. Peak knee flexion (during loading response and swing phase) during walking was significantly lower (both p<0.001) in children with HMS. Knee extension in mid stance during walking was significantly increased (p<0.001) in children with HMS. However, gait speed was not statistically (p=0.496) different between the two groups. Children with HMS had higher passive knee ROM than healthy children and also demonstrated abnormal knee motion during gait. Gait re-education and joint stability exercise programmes may be of value to children with HMS.

Visualisation of biomechanical data to assist therapeutic rehabilitation

PURPOSE: The biomechanics community have to date had limited success in communicating complex biomechanical data and analyses outside of their field. The authors have created an innovative prototype software tool to visualise objective dynamic movement data captured from older adults undertaking activities of daily living (ADLs). Evaluation of this tool has shown it to be a successful way of communicating the complexity of older adult mobility data in an accessible manner for non-biomechanical specialists and lay audiences(1,2). METHODS: A software tool was developed, which generates a 3D animated human 'stick figure', on which the biomechanical demands of ADLs are represented visually at the joints as a percentage of each individual's maximum capability using a continuous colour gradient from green at 0%, amber at 50%, through to red at 100% (Figure 1). The tool was evaluated using a qualitative methodology of interviews and focus groups, where older adults and professionals viewed a series of visualisations of dynamic movement data(3). RESULTS AND DISCUSSION: Analysis of focus group discussions facilitated by the visualizations revealed new kinds of dialogues about biomechanical issues. The method of visualising and presenting the data clearly enabled people without training in biomechanics, both professionals and lay older people, to access and interpret the biomechanical information, based on their background, knowledge of a field or their personal experience. Further, the common visual medium enabled the sharing of different insights without recourse to specialist terminology or knowledge. New kinds of dialogues occurred in focus groups between older people and professionals about their experiences, based on real understanding of where the mobility problems were occurring. New dialogues also emerged between professionals from a range of different disciplines, crucial for different aspects of the care, wellbeing or design of the built environment for older people. Neither of these would have been possible using current conventions of presenting biomechanical data. The visualisations also appear to allow a deeper understanding of the issues within professions, both in healthcare and in design. These findings have led to new research with five discrete yet complementary studies covering a range of clinical applications of this method for: i) mobility and exercise advice for the healthy older adult; ii) falls prevention; iii) rehabilitation of total knee replacement; iv) to enhance early mobilisation of acute stroke patients and v) to enhance biomechanical diagnosis and fitting of ankle foot orthoses (AFO) in late stage stroke.

Effect of ageing on isometric strength through joint range at knee and hip joints in three age groups of older adults

BACKGROUND

Strength of lower extremity muscles is an important determinant of mobility-based functional activities. Loss of strength with age produces functional limitation in activities of daily living such as rising from a chair or stair negotiation. However, there is limited information on the effect of age-related changes on the torque-producing ability of muscles through their ranges of joint motion.

OBJECTIVE

To investigate the effect of ageing on the torque-producing ability of lower extremity muscles in a large sample of older adults in three age groups.

METHODS

Eighty-two volunteers participated in this study and were divided into six groups according to their chronological age (60s, 70s and 80s and above) and gender (male, female). Isometric muscle strength was measured at the knee and hip joints at three positions through the joint range using a custom-built strain gauge torque dynamometer and a purpose built plinth.

RESULTS

The peak torque of major muscle groups of the knee and hip joints decreased with increasing age at all the three joint positions at which strength was tested. The 80-year-olds had 20% lower strength compared to the 60-year-olds. Age-related decrease in muscle strength was significant when comparing 80-year-olds with the 60-year-olds (p < 0.05). Strength loss was noted to be higher at the inner (muscle is shortened from mid-position) and outer (muscle is lengthened from mid-position) ranges of muscle action when compared with the mid-range position (mid-position). Gender-based differences were significant for all the strength tests (p < 0.05).

CONCLUSIONS

Strength decreased with increasing age at all the positions within joint range of motion for knee and hip joints. However, the percentage loss of muscle strength was different at different positions in the joint range. Our findings suggest that muscle strength was more preserved in the middle range of muscle function compared to the inner and outer range of muscle action. In older people, lower extremity muscles might be required to produce higher moments in joint positions that are not within the optimum mid-position for muscle action.

An electromyographical study to investigate the effects of patellar taping on the vastus medialis/vastus lateralis ratio in asymptomatic participants

It is commonly theorised that patellofemoral pain syndrome (PFPS) is caused by maltracking due to vastus medialis (VM) weakness relative to the vastus lateralis (VL). Despite this being a controversial theory, patellar taping is a commonly used technique that purports to correct this muscle imbalance by increasing the VM/VL ratio. The effects of different forms of taping on vasti muscle activity are still not known. The objective of this study was to investigate the effects of three different types of patellar taping on the VM/VL ratio in asymptomatic university students. Each participant performed a set of four single-legged squats under four separate taping conditions: A) medial, B) lateral, C) neutral, and D) no-tape. The condition sequence was randomised. The main outcome measure was the normalised VM/VL ratio, assessed by using surface electromyography. Secondary outcome measures were the normalised EMG activity of the VM and the VL. A convenience sample of 24 (17 females) students (22 +/- 10 years, M +/- SD) completed this study. The lateral taping condition produced small but significantly greater VM/VL ratios than the medial (p = 0.007) and neutral (p = 0.007) but not the no-tape (p = 0.123) condition. There were no significant differences between the medial, neutral, and no-tape conditions. These results question whether patellar taping can impart a clinically significant effect on the VM/VL ratio. The results of this study cannot be directly extrapolated to a patient population, and further research in the PFPS population is required before clinical recommendations can be made.

Between-day repeatability of knee kinematics during functional tasks recorded using flexible electrogoniometry

The objective of this study was to assess the between-day repeatability of knee kinematics during activities of daily living recorded by electrogoniometry. One rater assessed the peak knee angles and knee excursion of 15 subjects during 13 activities twice with an average of 22 days (range 5-31) between the two assessments. The 15 subjects included four patients one year after total knee replacement (TKR) surgery, five patients before TKR surgery and six age-matched controls. Intra-class correlation coefficients and Bland and Altman coefficient of repeatability were derived to analyse the results. Only the most affected leg of the patients and the right leg of the controls were used for analysis. Different measures of repeatability showed different results. Intra-class correlation coefficients were higher than 0.75 for peak values of all functions except sitting down and rising from a standard chair. However, coefficients of repeatability ranged from 5.6 degrees for the loading response in level walking to 39.8 degrees for stepping out of a bath. Both of these values are higher than clinically significant changes seen after total knee surgery. It was concluded that for a single assessment on individual patients, the functional knee motion as performed in this study did not have sufficient repeatability. However, if the measurements are used to assess the average changes before and after surgery in a group of patients, the assessment of knee motion during activities such as level walking, and slope and stair ascending and descending were found to be sufficiently repeatable.

Repeatability of joint proprioception and muscle torque assessment in healthy children and in children diagnosed with hypermobility syndrome

BACKGROUND

Impairment of joint proprioception in patients with hypermobility syndrome (HMS) has been well documented. Both joint proprioception and muscle torque are commonly assessed in patients with musculoskeletal complaints. It is unknown, however, if these measures change significantly on repeated application in healthy children and in children with HMS.

AIM

To investigate the between-days repeatability of joint proprioception and muscle torque in these groups.

METHODS

Twenty children (10 healthy and 10 with HMS), aged eight to 15 years, were assessed on two separate occasions (one week apart) for joint kinaesthesia (JK), joint position sense (JPS), and the extensor and knee flexor muscle torque of the knee. JK was measured using threshold to detection of passive movement. JPS was measured using the absolute angular error (AAE; the absolute difference between the target and perceived angles). Knee extensor and flexor muscle torque was normalized to body weight.

RESULTS

Intra-class correlation coefficients (ICC) for JK, extensor and flexor muscle torque were excellent in both groups (range 0.83 to 0.98). However, ICC values for JPS tests were poor to moderate in the two groups (range 0.18 to 0.56). 95% limits of agreement (LOA) were narrow in both cohorts for JK and muscle torque (indicating low systematic error) but wide for the JPS tests. 95% LOA also demonstrated that the measuring instruments used in this study had low between-days systematic error.

CONCLUSIONS

Based on ICC and 95% LOA, the repeatability of JK and muscle torque measurements was excellent in both healthy children and those with HMS. The JPS test can only be assessed with poor to moderate repeatability. The use of the JPS test in these children should be undertaken with caution.

Physical activity and quality of life: A study of a lower-limb amputee population

This cross-sectional descriptive study was initiated to investigate the relationship between physical activity and perceived quality of life in a lower-limb amputee population. The objective was to show which aspects of physical activity were most strongly linked to quality-of-life factors in this special patient group. The outcome measurements were two questionnaires: a section of the Trinity Amputation and Prosthetic Experience Scales (TAPES) and the World Health Organization Quality-of-Life Scale (WHOQOL-Bref). The former measures activity restriction and has Athletic, Functional, and Social subscales. The latter includes Physical, Psychological, Social, and Environmental domains, and measures the individual's perception of their quality of life. The two questionnaires were sent by post to 75 male and female participants with either trans-tibial or trans-femoral amputation who were receiving prosthetic care from a Glasgow-based rehabilitation and mobility centre and who met the inclusion criteria. All participants were over 18 years of age (mean age 66 years). In total, 25 participants returned the questionnaires-a response rate of 33%. According to analysis, 8 of the 12 relationships found were statistically significant. There was a very strong correlation between scores on the social elements of each questionnaire. The correlations between scores on the functional and athletic elements of the TAPES questionnaire and scores on the social element of the WHOQOL-Bref questionnaire were less strong. Our findings support the need for greater acknowledgement by healthcare professionals involved in the care of those with amputation about the importance of the patient's social relationships with friends and family. Education about the importance of increasing and maintaining a level of physical activity conducive to health benefits should be implemented within a supportive sociable environment for the patient with lower-limb amputation.

Knee kinematics in functional activities seven years after total knee arthroplasty

BACKGROUND

Detailed knowledge of knee kinematics during functional activities is lacking in current studies on the long-term outcome of total knee replacement surgery. The aim of this study was to assess functional knee kinematics using flexible electrogoniometry in patients seven years after unilateral primary total knee arthroplasty for osteoarthritis.

METHODS

The knee joint functional movement of a cohort of patients (n=19) with knee osteoarthritis was assessed using electrogoniometry before surgery and 18-24 months and seven years after total knee surgery. The mean age of the patients (11 women and 8 men) at the time of the pre-surgery assessment was 67 years old (SD 8.0). Patient function was also assessed using the Knee Society Score and WOMAC osteoarthritis Index.

FINDINGS

The function components of the Knee Society and WOMAC scores were significantly decreased at seven years compared to 18-24 months after surgery (both P<0.05). However, the majority of the functional knee flexion values derived from electrogoniometry did not decrease. Seven years after surgery, knee excursion during ascending and descending stairs was significantly improved compared to 18-24 months after surgery (both P<0.01).

INTERPRETATION

The finding that functional knee motion continues to improve between 18-24 months and seven years post-surgery is of interest to both patients and those responsible for their treatment planning. Further, it was shown that the WOMAC and Knee Society Scores do not follow the same trends as the patients' functional knee kinematics seven years after total knee replacement surgery.

The effect of patella resurfacing in total knee arthroplasty on functional range of movement measured by flexible electrogoniometry

BACKGROUND

The need for patella resurfacing remains an area of considerable controversy in total knee replacement surgery. There would appear to be no reported evidence on the effect of patella resurfacing on knee function, as measured by functional range of movement used in a series of tasks, in patients undergoing knee replacement. The object of this study was to measure knee joint motion during functional activities both prior to and following total knee replacement in a randomised group of patients with and without patella resurfacing and to compare these patient groups with a group of normal age-matched subjects.

METHODS

The study design was a double blinded, randomised, prospective, controlled trial. The knee joint functional ranges of movement of a group of patients (n=50, mean age=70 years) with knee osteoarthritis were investigated prior to and following total knee arthroplasty (4 months and 18-24 months) along with a group of normal subjects (n=20, mean age=67). Patients were randomly allocated into two groups, those who received patella resurfacing (n=25) and those who did not (n=25). Flexible electrogoniometry was used to measure the flexion-extension angle of the knees with respect to time in eleven functional activities.

FINDINGS

No statistically significant differences (alpha level 0.05) in joint excursion of the affected knee were found between patients who received patella resurfacing and those who did not.

INTERPRETATION

Routine patella resurfacing in a typical knee arthroplasty population does not result in an increase in the functional range of movement used after knee replacement.

The effect of total knee arthroplasty on joint movement during functional activities and joint range of motion with particular regard to higher flexion users

PURPOSE

To evaluate active and functional knee excursion of patients before and after total knee arthroplasty (TKA) and to determine whether TKA restores quality of life related to functional activities of daily living.

METHODS

Electrogoniometry was used to measure the functional movement of the knee during 11 activities of daily living in 50 patients who underwent TKA. These data were compared with the patient's active range of motion and quality-of-life scores.

RESULTS

A cut-off point existed between loss and gain in flexion at between 90 and 95 degrees of preoperative active flexion. Two thirds of patients had preoperative flexion of more than 90 degrees, 83% of them had reduced flexion postoperatively. The remaining one third had preoperative flexion of 90 degrees or less, 85% of them had improved flexion postoperatively. A similar pattern of loss and gain occurred for functional movement of the knee. Reduced functional range was associated with significantly reduced physical quality of life compared with age-matched healthy subjects.

CONCLUSION

Although TKA offers excellent pain relief and contributes to the overall well-being of the patient, these results suggest that it also leads to a reduced range of active and functional motion in the majority of patients. This is associated with a lower-than-normal physical quality of life. The design of implants and rehabilitation programmes should be reconsidered so that better range of motion and quality of life can be achieved for patients.

Male infertility: risk factors in Mongolian men

AIM

To determine the most common risk factors of male infertility in Mongolian men attending an infertility clinic.

METHODS

A prospective, case-control study was conducted in which 430 men were enrolled. All the men had sought their first infertility evaluation between 1998-2002 in the State Research Center on Maternal Child Health, Ulaanbaatar, Mongolia. They were divided into two groups depending on the results of their semen analysis: 191 with abnormal semen and 239 with normal semen profile. Univariate and multivariate analyses were performed to determine any association between risk factors and semen abnormality.

RESULTS

Logistic regression analysis demonstrated that the testicular volume, a history of sexually transmitted infections (STI), epididymitis and testicular damage all have statistically significant associations with semen abnormality, when controlled for multiple risk factors. Adjusted odds ratios of 3.4 for mumps orchitis, 2.3 for other orchitis and 3.9 for testicular injury were found. Gonorrhoea, the most commonly reported STIs in this study, gave an adjusted odds ratio of 1.0 for having one or more sperm abnormality. An adjusted odds ratio for subjects with a history of other STIs was 2.7. However, as a predictor of azoospermia, STIs had very high odds ratio, being 5.6 in patients with gonorrhoea and 7.6 in patients with other STIs.

CONCLUSION

A history of pathology involving testicular damage appeared to have the strongest impact on male infertility in Mongolia. STIs have less impact on semen quality except when complicated by orchitis, epididymitis and vasal obstruction.

Assessment of menstrual blood loss in Belgian users of the frameless copper-releasing IUD with copper surface area of 200 mm2 and users of a copper-levonorgestrel-releasing intrauterine system

OBJECTIVE

This study was conducted to evaluate the effect of a miniaturized frameless copper IUD (GyneFix 200 small) and a copper-levonorgestrel (GynePlant) intrauterine system (IUS) on the amount of menstrual blood loss (MBL).

METHODS

In 60 Belgian women using GyneFix 200 and 21 using GynePlant, MBL was assessed with the visual assessment technique.

RESULTS

MBL scores in GyneFix 200 users did not change from baseline during the mean observation period of 31 months. In GynePlant users, mean MBL scores decreased by at least 50% in all but one user.

CONCLUSION

The impact of copper IUDs on MBL can be minimized by reducing the surface area of the foreign body. Reduction of MBL, without causing amenorrhea, can be obtained by adding levonorgestrel.

Assessment of menstrual blood loss in women with ideopathic menorrhagia using the frameless levonorgestrel-releasing intrauterine system

OBJECTIVE

This study was conducted to evaluate the effect of a "low-dose" levonorgestrel (LNG)-releasing intrauterine system (IUS) on the amount of menstrual blood loss (MBL) in women with ideopathic menorrhagia.

METHODS

Menstrual blood loss was assessed with the visual assessment technique in 12 Belgian FibroPlant-LNG users with menorrhagia. In addition, ferritin levels were measured.

RESULTS

The median MBL, evaluated by the visual scoring technique, decreased by more than 90%. The ferritin levels increased significantly during treatment with the levonorgestrel system.

CONCLUSION

This study confirms previous MBL studies conducted with the FibroPlant-LNG IUS demonstrating the efficacy of the LNG-IUS to significantly reduce the amount of MBL in women with menorrhagia. The strong endometrial suppression is the principal mechanism explaining the effect on MBL. The therapeutic effect of this contraceptive method is highly desirable, particularly in women with heavy bleeding or anemia, as other treatment modalities are less effective, more costly, more invasive or inaccessible. The simple design characteristics and anchoring system account for minimizing the occurrence of complaints of pain and expulsion.

Assessment of menstrual blood loss in Brazilian users of the frameless copper-releasing IUD with copper surface area of 330 mm2 and the frameless levonorgestrel-releasing intrauterine system

OBJECTIVE

This study was conducted to evaluate the effect of two types of IUDs on the amount of menstrual blood loss (MBL): the frameless copper-releasing intrauterine device (IUD) with copper surface area of 330 mm2 (GyneFix; Contrel Research, Ghent, Belgium) and the frameless levonorgestrel (LNG)-releasing intrauterine system (IUS) releasing 14 microg per day (FibroPlant-LNG; Contrel Research). Heavy and abnormal MBL is the main reason for discontinuation of intrauterine devices.

METHODS

In 20 Brazilian women using GyneFix 330 and 32 using FibroPlant-LNG, respectively, MBL was measured by the quantitative alkaline hematin technique. In addition, ferritin levels were measured in GyneFix 330 and FibroPlant-LNG users.

RESULTS

MBL with GyneFix 330, measured over a 24-month period, increased but was less when compared with TCu380A. Ferritin levels with GyneFix 330 were not affected in contrast with TCu380A. In FibroPlant-LNG users, mean MBL decreased by about 90% and ferritin levels increased significantly.

CONCLUSIONS

The authors confirm earlier reports that, especially for women with low body iron stores and heavy menstrual bleeding, there is an order of preference for IUD use to minimize MBL. The choice should first be a progestin-releasing IUS, then a copper IUD, which has the least effect on menstrual bleeding, such as the frameless GyneFix IUD.

Establishing the reliability of Mobility Milestones as an outcome measure for stroke

Baer GD, Smith MT, Rowe PJ, Masterton L. Establishing the reliability of mobility milestones as an outcome measure for stroke. Arch Phys Med Rehabil 2003;84:977-81.

OBJECTIVE

To establish intrarater, interrater, and test-retest reliability of a standardized measure of mobility, "mobility milestones," incorporating sitting balance, standing balance, and walking ability.

DESIGN

Repeated-measures reliability study by using video data of patients with stroke.

SETTING

Physiotherapy and rehabilitation departments in Scotland.

PARTICIPANTS

Forty physiotherapists recruited from within the Lothian region: 20 senior physiotherapists with at least 3 years of experience working with neurologic patients and 20 staff grade physiotherapists with less than 12 months of experience working with neurologic patients.

INTERVENTION

Videotape comprising 40 clips (36 original clips, 4 repeated clips) of stroke patients of differing levels of ability attempting the mobility milestones was produced. After a short training session in the interpretation and application of the mobility milestones, each physiotherapist viewed the tape separately and scored whether the milestone had been achieved or not. This was repeated at a separate test session 2 weeks later.

MAIN OUTCOME MEASURE

Score for each mobility milestone.

RESULTS

Kappa statistics were used to determine interrater reliability and showed good (.61-.80) to very good (.81-1.0) reliability for 3 of 4 milestones. Intraclass correlation coefficients (ICCs) were used to determine intrarater reliability of the 4 repeated clips and showed 75% of all subjects had high (ICC(2,1)=.91-1.0) reliability. The ICC(2,1) for test-retest reliability showed a similar pattern, with 70% of subjects showing good (.81-.90) or high (.91-1.0) reliability.

CONCLUSIONS

The mobility milestones showed favorable levels of reliability when used by experienced or novice physiotherapists. The milestones can be adopted as a simple clinical outcome measure for use with stroke. Further research is required to establish reliability levels when the measure is used by different rehabilitation professionals.

The effect of independent practice of motor tasks by stroke patients: a pilot randomized controlled trial

OBJECTIVE

To investigate the effect of independent practice of sitting balance as an addition to standard physiotherapy treatment for patients with stroke.

DESIGN

Randomized controlled trial, using blocked randomization procedure with 2:1 ratio.

SUBJECTS

Inpatients with diagnosis of stroke, having achieved one minute of independent sitting balance but not yet achieved 10 independent steps, and with no known previous disabilities, pathology or neurological deficit affecting mobility prior to stroke.

INTERVENTION

A four-week regime of independent practice aimed at improving aspects of balance, as an addition to standard physiotherapy treatment based on the Bobath Approach.

MAIN OUTCOME MEASURE

Proportion of patients achieving 'normal' symmetry of weight distribution during sitting, standing, rising to stand, sitting down, and reaching.

RESULTS

Nineteen subjects were randomized to the control group; nine to the intervention group. There were no clinically significant differences in measured outcome between the groups.

CONCLUSIONS

The regime of independent practice had no measured beneficial effect on the balance ability of patients with recently acquired stroke.

Knee joint functional range of movement prior to and following total knee arthroplasty measured using flexible electrogoniometry

The functional ranges of movement of the knee were investigated in a group of patients with knee osteoarthritis (n = 42, mean age 70 years) before, 4 months and at 18-24 months after total knee arthroplasty and then compared with age matched normal subjects (n = 20, mean age 67 years). Flexible electrogoniometry was used to record the maximum flexion-extension angle, the minimum flexion-extension angle and flexion-extension excursions of both knees during eleven functional activities along with the active and passive knee joint range of motion measured using a manual goniometer. Over the eleven functional activities the patients pre-operatively exhibited 28% less knee joint excursion than normal age matched subjects. By 18-24 months following total knee arthroplasty only 2% of this deficit was recovered. Statistically this recovery was only significant in level walking, slope ascent and slope descent. A greater range of movement was measured in a non-weight bearing position than was used in weight bearing functional activity. It is concluded that total knee arthroplasty gives rise to little improvement in knee motion during functional activities and that functional range of movement of the knee remains limited when compared to normal knee function for a minimum of 18 months following operation.

The use of colposcopy in assessing vaginal irritation in research

Since the early 1990s, colposcopy of the vagina and cervix has been used in the development of vaginal products in order to detect epithelial changes that may increase the likelihood of HIV or acquisition of other sexually transmitted diseases. As part of a continued effort to examine and define the role of colposcopy in a research setting, the Contraceptive Research and Development Program (CONRAD) and the International Working Group on Microbicides (IWGM), in association with the United Nations Program for AIDS (UNAIDS) sponsored a conference entitled, 'The Use of Colposcopy in Assessing Vaginal Irritation in Research', held in Washington, DC in January 1999. This is a report of that conference. The World Health Organization's colposcopy procedure and nomenclature, published in 1995, were reviewed and changes were recommended. The revised procedure involves colposcopic examination of the external genitalia, naked eye examination of the cervix, fornices, and vaginal walls, followed by lavage and colposcopic examination of those areas, and sampling as appropriate for microscopic examination. Revised nomenclature replaces the terms used for findings with descriptions of what is actually seen. Digital video imaging and testing for inflammatory markers may be adjuncts to colposcopy and should be further studied. Other areas requiring additional research include the natural history of colposcopic changes, factors other than product use that may affect colposcopic findings, the clinical significance of findings, and the procedure which best assesses these findings.

Knee joint kinematics in gait and other functional activities measured using flexible electrogoniometry: how much knee motion is sufficient for normal daily life?

The knee joint kinematics of a group (n=20) of elderly normal subjects (mean age=67 years) were investigated using flexible electrogoniometry. The flexion-extension angle of the knee was recorded during a range of functional activities performed as part of a circuit in and around the hospital. The functions analysed including gait, walking on slopes, stair negotiation, the use of standard and low chairs and a bath. The data were used to produce the pattern of joint angulation against the percentage of the cycle for each individual conducting each activity. Further the maximum and minimum knee joint angles and the excursion of the joint during the cycle were identified. The results indicate gait and slopes require less than 90 degrees of knee flexion, stairs and chairs 90-120 degrees of flexion and a bath approximately 135 degrees of flexion. The data suggests that 110 degrees of flexion would seem a suitable goal for the rehabilitation of motion in the knee. It is concluded that flexible electrogoniometry is a suitable and practical method for evaluating knee motion during a range of functional activities.

What is balance?

Balance is a term frequently used by health professionals working in a wide variety of clinical specialities. There is no universally accepted definition of human balance, or related terms. This article identifies mechanical definitions of balance and introduces clinical definitions of balance and postural control. Postural control is defined as the act of maintaining, achieving or restoring a state of balance during any posture or activity. Postural control strategies may be either predictive or reactive, and may involve either a fixed-support or a change-in-support response. Clinical tests of balance assess different components of balance ability. Health professionals should select clinical assessments based on a sound knowledge and understanding of the classification of balance and postural control strategies.

Chlamydial urethral infection in male students in Chiang Mai: a screening test of urine deposits by enzyme immunoassay (EIA)

Adolescent males are considered to be an important genital chlamydial reservoir. However, there has been little information on urethral chlamydial infection in Thai adolescent males. About one fourth of males who are genital chlamydial reservoirs are asymptomatic. An appropriate means of defining the extent of chlamydial infection in adolescent males would be a non-invasive screening survey, instead of the conventional method of a deep swab cell culture, which is painful. The objectives of this study were to estimate the prevalence and to determine what factors should indicate the use of a screening test for urethral chlamydial infection in adolescent males residing in Chiang Mai. Chlamydial urethritis was detected by examining urine deposits for chlamydial antigen by enzyme immunoassay (EIA).

A new system for the measurement of displacements of the human body with widespread applications in human movement studies

This paper reports the development, construction and use of a new system for the measurement of linear kinematics in one, two or three dimensions. The system uses a series of rotary shaft encoders and inelastic tensioned strings to measure the linear displacement of key anatomical points in space. The system is simple, inexpensive, portable, accurate and flexible. It is therefore suitable for inclusion in a variety of motion analysis studies. Details of the construction, calibration and interfacing of the device to an IBM PC computer are given as is a full mathematical description of the appropriate measurement theory for one, two and three dimensions. Examples of the results obtained from the device during gait, running, rising to stand, sitting down and pointing with the upper limb are given. Finally it is proposed that, provided the constraints of the system are considered, this method has the potential to measure a variety of functional human movements simply and inexpensively and may therefore be a valuable addition to the methods available to the motion scientist.

Development of a low-cost video vector for the display of ground reaction forces during gait

Video vector systems offer a simple and valuable tool suitable for evaluating and analysing the biomechanics of human motion. These systems are capable of widespread applications in education, clinical evaluation and research. However, the literature indicated that current video vector systems are expensive and not widely available. The work presented in this study indicates an alternative method of constructing a video vector system which is inexpensive and relatively simple to build. The system uses a VGA to video adaptor to convert computer-generated graphics of the ground reaction force into a video formet. This picture can then be overlaid on to a video picture of the moving subject using a video mixer. By careful positioning of the camera and suitable perspective drawing of the computer image a true representation of the relationship between the force vector and the subject can be produced. The system has been found to be reliable, versatile and robust and has been used for a variety of motion analysis tasks. It is hoped that the work contained in this paper will encourage others to construct their own video vector systems using similar commercially available components and hence benefit from the considerable advantages that such a system can offer. This paper describes the design and construction of a simple, inexpensive video vector system which has been shown to be a useful biomechanical technique with widespread applications in the educational, clinical and research environments.

The association of Chlamydia trachomatis/gonococcal infection and tubal factor infertility

OBJECTIVE

To determine the association of past Chlamydia trachomatis and past Neisseria gonorrhoeae infection with tubal factor infertility.

METHODS

A cross-sectional study was conducted. Cases consisted of 55 primary infertile women with laparoscopy confirmed tubal damage (group A) and their husbands, consecutively attending the Infertility Unit at Maharaj Nakorn Chiang Mai Hospital between 1990 and 1992; and 58 primary infertile women with laparoscopy confirmed normal tubes (group B) and their husbands, consecutively attending the same hospital over the same period. Controls consisted of 59 postpartum women (group C) and their husbands omitted to the same hospital over the same period as cases. Past chlamydial and gonococcal infections were assessed by measuring serum IgG antibodies by enzyme immunoassay (EIA). The EIA antigens consisted of purified elementary bodies of C. trachomatis serovar L1, or purified alpha pili of N. gonorrhoeae strain P9.

RESULTS

The prevalence of positive IgG antibody to gonococcal pili in sera from group A was 29.1%, significantly higher than the prevalence of 5.2% in group B or 3.4% in group C (p = 0.000). The husbands of women in group A had a significantly higher prevalence of IgG antibody to gonococcal pili (36.4%) than the husbands of women in group B (8.6%) or group C (18.6%) (p = 0.002). There was no significant difference in positive IgA antibody between case and control groups. After controlling for age, group A showed significantly higher prevalences of past gonorrhea (OR = 32.4, 95% CI 4.3, 242.2) and past chlamydial infection (OR = 3.2, 95% CI 1.2, 8.5) than group C. The husbands of women in group A also had higher prevalences of both types of infection than the husbands of women in group C; the odds ratios for past gonorrhea or chlamydial infections were 2.8 (95% CI 1.1, 6.9) and 2.9 (95% CI 1.2, 7.1), respectively. Neither infertile women with normal tubes (group B) nor their husbands showed any difference when compared with controls.

CONCLUSION

These results suggest that in this region of northern Thailand there is an association between past gonorrhea and past chlamydial infection and tubal factor infertility.