Psychometric properties of the 12-item Knee injury and Osteoarthritis Outcome Score (KOOS-12) Spanish version for people with knee osteoarthritis.

To evaluate the validity, reliability, and responsiveness to change of the 12-item Knee injury and Osteoarthritis Outcome Score (KOOS) Spanish version questionnaire. This study was based on a questionnaire validation design. A cross-sectional survey of 199 patients with knee osteoarthritis (KOA) and ten healthy controls was studied to evaluate the validity and reliability of KOOS-12. One hundred and sixteen patients were assessed for test-retest reliability, and 38 patients were included for a responsiveness assessment. Structural validity was assessed by the confirmatory factor analysis (CFA). Item response theory-based methods were used to determine the performance of the items. Internal consistency reliability was appropriate for all scales (Cronbach's alpha = 0.85-0.94). The intra-class correlation coefficient of KOOS-12 scales ranged from 0.60 to 0.71. The CFA and generalized partial credit model showed that KOOS-12 scales presented a good overall model fit. No differential item functioning was found. Convergent validity was demonstrated by strong correlations (Spearman's rho ≥ 0.70) with KOOS, International Knee Documentation Committee subjective knee evaluation form (IKDC), and Knee Intermittent and Constant Osteoarthritis Pain (ICOAP). Known-groups validity showed that KOOS-12 well discriminated subgroups of patients (radiographic severity and nutritional status). Standardized response means for KOOS-12 scales were ≥ 0.75. Changes in KOOS-12 scales had a moderate to strong correlation (Pearson's r ≥ 0.40) with the changes in the KOOS, ICOAP, and IKDC scales. The KOOS-12 Spanish version is a valid, reliable, and responsiveness to change questionnaire to measure patients' opinions about their knee and associated problems in Mexican subjects with KOA. Key Points • KOOS-12 is a short self-reported measure that assesses patient's opinions about the difficulties they experience due to problems with their knee and also covers aspects of pain, functional limitations, and knee-related quality of life. • The Spanish version of KOOS-12 questionnaire is a valid instrument for measuring the patients' opinions about their knee and associated problems, and is both reliable and responsiveness to change.

[Treatment of recurrent giant cell tumor of the tibia with en bloc resections, bone transport and arthrodesis using an AO type external fixations system. A case report]. / Resección en bloque, transporte óseo y artrodesis con fijador tubular AO del tumor de células gigantes recurrente de tibia. Reporte de un caso.

INTRODUCTION: The primary treatment for the giant cell tumor (GCT) at the knee level, both distal femur and proximal tibia remains curettage and application of methyl methacrylate. In the cases where recurrence occurs, controversy exists in the decision making algorithm whether to preserve the joint, or to perform en bloc resection. CASE REPORT: We report a case of GCT that relapsed at proximal tibia in a stage III of Enneking, in a 26 year old patient, that was handled with en bloc resection, transportation and bone arthrodesis using an AO type tubular external fixator (Synthes). After two years of evolution there was no evidence of tumor relapse, the limb was preserved and we obtained a solid arthrodesis, and an acceptable gait. DISCUSSION: We believe this procedure is a feasible option and an alternative to tumoral prosthesis and amputation. However, despite the success obtained with this procedure, we strongly recommend to assess the functional reconstruction procedures on an individual basis and according to the need of each patient.