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.

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.

Multivariate prediction of clarified butter composition using raman spectroscopy

Raman spectroscopy has been used to predict the abundance of the FA in clarified butterfat that was obtained from dairy cows fed a range of levels of rapeseed oil in their diet. Partial least squares regression of the Raman spectra against FA compositions obtained by GC showed good prediction for the five major (abundance >5%) FA with R2 = 0.74-0.92 and a root mean SE of prediction (RMSEP) that was 5-7% of the mean. In general, the prediction accuracy fell with decreasing abundance in the sample, but the RMSEP was <10% for all but one of the 10 FA present at levels >1.25%. The Raman method has the best prediction ability for unsaturated FA (R2 = 0.85-0.92), and in particular trans unsaturated FA (best-predicted FA was 18:1 t delta9). This enhancement was attributed to the isolation of the unsaturated modes from the saturated modes and the significantly higher spectral response of unsaturated bonds compared with saturated bonds. Raman spectra of the melted butter samples could also be used to predict bulk parameters calculated from standard analyzes, such as iodine value (R2 = 0.80) and solid fat content at low temperature (R2 = 0.87). For solid fat contents determined at higher temperatures, the prediction ability was significantly reduced (R2 = 0.42), and this decrease in performance was attributed to the smaller range of values in solid fat content at the higher temperatures. Finally, although the prediction errors for the abundances of each of the FA in a given sample are much larger with Raman than with full GC analysis, the accuracy is acceptably high for quality control applications. This, combined with the fact that Raman spectra can be obtained with no sample preparation and with 60-s data collection times, means that high-throughput, on-line Raman analysis of butter samples should be possible.