RESUMO
Background: The Banff Patellofemoral Instability Instrument (BPII) 2.0 is a disease-specific quality of life questionnaire for patients with patellofemoral instability. While good psychometric properties have been demonstrated, the data lack cross-cultural validity, construct validity, and an established measurement error. Purpose: To (1) translate and cross-culturally adapt the BPII 2.0 to the Norwegian version (BPII 2.0-No) and (2) examine the psychometric properties of the Norwegian version. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: The BPII 2.0 was translated according to international guidelines. A cohort of 100 patients surgically treated for recurrent patellofemoral instability completed the BPII 2.0-No, related outcome measures (Norwich Patellar Instability Score, International Knee Documentation Committee Subjective Knee Form 2000, Knee injury and Osteoarthritis Outcome Score, and Tampa Scale of Kinesiophobia), and functional tests (Y-Balance Test-Lower Quarter, single-leg hop tests, and knee extension strength) before and/or 6 months after surgery. We evaluated the face and content validity, internal consistency (Cronbach α), test-retest reliability (intraclass correlation coefficient [ICC]), measurement error (SEM and smallest detectable change at the individual [SDCind] and group levels [SDCgroup]). Construct validity was assessed by testing 9 hypotheses on the correlation between the BPII 2.0-No and the outcome measures/functional tests (Pearson r). Results: The BPII 2.0-No had good face and content validity. Internal consistency was excellent (α = .95), and no floor or ceiling effects were found. Test-retest reliability was high (ICC2,1 = 0.87; 95% CI, 0.77-0.93), and measurement error was low (SEM = 7.1). The SDCind was 19.7 points and the SDCgroup was 2.8 points. Eight of the 9 hypotheses regarding construct validity were confirmed. Conclusion: The BPII 2.0-No was found to be valid and reliable. This study adds further knowledge on the measurement properties of the BPII 2.0 that can be used internationally.
RESUMO
PURPOSE: The purpose of this study was to evaluate clinical and radiological results in patients operated for recurrent patellar instability with a surgical approach consisting of Insall proximal realignment with/without tibial tubercle osteotomy (TTO). METHODS: Patients that underwent surgery for recurrent patellar instability at one centre with a uniform technique between 2004 and 2020 were included. Eligible patients were assessed by clinical examination and the disease-specific Banff Patellofemoral Instability Instrument 2.0 (BPII 2.0). Pre- and postoperative radiographs were analysed for patellofemoral osteoarthritis (OA) according to Iwano. Preoperative Magnetic Resonance Imaging (MRI) and radiographs were analysed for anatomical risk factors for patellar instability. Student t-test, chi-square test and ANOVA-analyses were used to investigate whether anatomical risk factors and/or patient characteristics could predict an inferior outcome. RESULTS: Forty-six patients (47 knees) were included at a mean follow-up time of 6.6 years (SD 4.6; range 1-17). Mean BPII 2.0 score was 60.4 (SD 18.4; range 26-98), and 10.6% (n = 5) had suffered a postoperative redislocation. Progression to evident patellofemoral OA was seen in 15% of the patients (p < 0.05). The presence of pathoanatomic risk factors did not correlate with recurrent postoperative instability or inferior BPII 2.0 score at the final evaluation. CONCLUSION: Patients treated with the current approach reported acceptable medium- to long-term results, but the risk of patellofemoral OA progression is significant. These findings add to the knowledge of expected outcomes after procedures involving Insall proximal realignment, and can guide clinical decision making for surgeons using similar methods. LEVEL OF EVIDENCE: Level IV, case series.
