Multi-slice ultrasound image calibration of an intelligent skin-marker for soft tissue artefact compensation.

In this paper, a novel multi-slice ultrasound (US) image calibration of an intelligent skin-marker used for soft tissue artefact compensation is proposed to align and orient image slices in an exact H-shaped pattern. Multi-slice calibration is complex, however, in the proposed method, a phantom based visual alignment followed by transform parameters estimation greatly reduces the complexity and provides sufficient accuracy. In this approach, the Hough Transform (HT) is used to further enhance the image features which originate from the image feature enhancing elements integrated into the physical phantom model, thus reducing feature detection uncertainty. In this framework, slice by slice image alignment and calibration are carried out and this provides manual ease and convenience.

Development and validation of a VISA tendinopathy questionnaire for greater trochanteric pain syndrome, the VISA-G.

BACKGROUND: Greater trochanteric pain syndrome (GTPS) is common, resulting in significant pain and disability. There is no condition specific outcome score to evaluate the degree of severity of disability associated with GTPS in patients with this condition. OBJECTIVE: To develop a reliable and valid outcome measurement capable of evaluating the severity of disability associated with GTPS. METHODS: A phenomenological framework using in-depth semi structured interviews of patients and medical experts, and focus groups of physiotherapists was used in the item generation. Item and format clarification was undertaken via piloting. Multivariate analysis provided the basis for item reduction. The resultant VISA-G was tested for reliability with the inter class co-efficient (ICC), internal consistency (Cronbach's Alpha), and construct validity (correlation co-efficient) on 52 naïve participants with GTPS and 31 asymptomatic participants. RESULTS: The resultant outcome measurement tool is consistent in style with existing tendinopathy outcome measurement tools, namely the suite of VISA scores. The VISA-G was found to be have a test-retest reliability of ICC2,1 (95% CI) of 0.827 (0.638-0.923). Internal consistency was high with a Cronbach's Alpha of 0.809. Construct validity was demonstrated: the VISA-G measures different constructs than tools previously used in assessing GTPS, the Harris Hip Score and the Oswestry Disability Index (Spearman Rho:0.020 and 0.0205 respectively). The VISA-G did not demonstrate any floor or ceiling effect in symptomatic participants. CONCLUSION: The VISA-G is a reliable and valid score for measuring the severity of disability associated GTPS.

Precision analysis of a multi-slice ultrasound sensor for non-invasive 3D kinematic analysis of knee joints.

Currently the standard clinical practice for measuring the motion of bones in a knee joint with sufficient precision involves implanting tantalum beads into the bones to act as fiducial markers prior to imaging using X-ray equipment. This procedure is invasive in nature and exposure to ionizing radiation imposes a cancer risk and the patient's movements are confined to a narrow field of view. In this paper, an ultrasound based system for non-invasive kinematic evaluation of knee joints is proposed. The results of an initial analysis show that this system can provide the precision required for non-invasive motion analysis while the patient performs normal physical activities.

Bicruciate-stabilised total knee replacements produce more normal sagittal plane kinematics than posterior-stabilised designs.

Bicruciate-stabilised total knee replacement (TKR) aims to restore normal kinematics by replicating the function of both cruciate ligaments. We performed a prospective, randomised controlled trial in which bicruciate- and posterior-stabilised TKRs were implanted in 13 and 15 osteo-arthritic knees, respectively. The mean age of the bicruciate-stabilised group was 63.9 years (SD 10.00) and that of the posterior-stabilised group 63.2 years (SD 6.7). A control group comprised 14 normal subjects with a mean age of 67.9 years (SD 7.9). The patellar tendon angle (PTA) was measured one week pre-operatively and at seven weeks post-operatively during knee extension, flexion and step-up exercises. At near full extension during step-up, the bicruciate-stabilised TKR produced a higher mean PTA than the posterior-stabilised TKR, indicating that the bicruciate design at least partially restored the kinematic role of the anterior cruciate ligament. The bicruciate-stabilised TKR largely restored the pre-operative kinematics, whereas the posterior-stabilised TKR resulted in a consistently lower PTA at all activities. The PTA in the pre-operative knees was higher than in the control group during the step-up and at near full knee extension. Overall, both groups generated a more normal PTA than that seen in previous studies in high knee flexion. This suggested that both designs of TKR were more effective at replicating the kinematic role of the posterior cruciate ligament than those used in previous studies.

Does ultrasound correlate with surgical or histologic findings in greater trochanteric pain syndrome? A pilot study.

BACKGROUND: Greater trochanteric pain syndrome can be severely debilitating. Ideal imaging modalities are not established, treatments are not reliably evaluated, and the underlying pathology is not well understood. QUESTIONS/PURPOSES: Using surgical and histopathology findings as a gold standard, we therefore determined the positive predictive value of preoperative ultrasound assessment for greater trochanteric pain syndrome recalcitrant to nonoperative management. In addition, we report the outcomes of gluteal tendon reconstructive surgery using validated clinical and functional outcome tools and evaluate the contribution of the tendon and bursa to greater trochanteric pain syndrome. PATIENTS AND METHODS: We reviewed 24 patients who had combined gluteal tendon reconstruction and bursectomy. Preoperative ultrasound imaging was compared with surgical findings. In the absence of a greater trochanteric pain syndrome specific outcome tool, surgical outcomes for pain and function were assessed via a 100-mm visual analog scale, the modified Harris hip score, and the Oswestry Disability Index. Strength also was measured. The tendon and bursa tissue collected at surgery was histopathologically reviewed. RESULTS: In our small study, ultrasound had a high positive predictive value for gluteal tendon tears (positive predictive value = 1.0). Patients reported high levels of pain relief and function after surgery; tendon and bursa showed pathologic changes. CONCLUSIONS: Ultrasound appears to be clinically useful in greater trochanteric pain syndrome; reconstructive surgery seems to relieve pain and the histopathologic findings show tendinopathy and bursa pathology coexist in greater trochanteric pain syndrome. LEVEL OF EVIDENCE: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Quality of life after infection in total joint replacement.

PURPOSE: To compare the health-related quality of life and functional outcomes of patients with and without periprosthetic infection after total joint replacement (TJR). METHODS: 62 uncomplicated TJRs and 34 TJRs complicated with deep infection were compared using a visual analogue scale for satisfaction, the Western Ontario and McMaster Universities Osteoarthritis Index, Assessment of Quality of Life, and Short Form-36. RESULTS: Patients with complicated TJR had significantly poorer satisfaction in outcome (p<0.0001) and disease-specific functional outcomes (p<0.0001). Six of the 8 health-related quality-of-life scores were also significantly poorer (p<0.05). These results persisted after controlling for age, sex, and follow-up period in a multiple regression analysis. CONCLUSION: Infection following TJR reduces patient satisfaction and seriously impairs functional health status and health-related quality of life. When hospitals are balancing the costs of preventative measures with the costs of treating infection in TJR, the effect on patients' quality of life must be considered. Our findings argue strongly for allocation of health care resources to minimise the occurrence of infection after TJR.

Does anterior cruciate ligament reconstruction restore normal knee kinematics?: A prospective MRI analysis over two years.

This prospective study used magnetic resonance imaging to record sagittal plane tibiofemoral kinematics before and after anterior cruciate ligament reconstruction using autologous hamstring graft. Twenty patients with anterior cruciate ligament injuries, performed a closed-chain leg-press while relaxed and against a 150 N load. The tibiofemoral contact patterns between 0 degrees to 90 degrees of knee flexion were recorded by magnetic resonance scans. All measurements were performed pre-operatively and repeated at 12 weeks and two years. Following reconstruction there was a mean passive anterior laxity of 2.1 mm (sd 2.3), as measured using a KT 1000 arthrometer, and the mean Cincinnati score was 90 (sd 11) of 100. Pre-operatively, the medial and lateral contact patterns of the injured knees were located posteriorly on the tibial plateau compared with the healthy contralateral knees (p=0.014), but were no longer different at 12 weeks (p=0.117) or two years postoperatively (p=0.909). However, both reconstructed and healthy contralateral knees showed altered kinematics over time. At two years, the contact pattern showed less posterior translation of the lateral femoral condyle during flexion (p<0.01).