Avaliação quantitativa das forças laterais da patela: ressonância magnética estática e cinemática

Abstract

OBJECTIVE: To evaluate the usefulness of combining static and kinematic magnetic resonance imaging in the evaluation of the femoropatellar joint. MATERIALS AND METHODS: Twenty healthy volunteers (40 knees) and 23 patients (43 knees) were submitted to both static and kinematic magnetic resonance imaging on a 1.5 tesla whole-body magnetic resonance scanner. The knees were positioned at 30º flexion with the quadrature knee coil at the inner end of the examination table. The patellar translation was evaluated by measurements of bisect offset, lateral patellar displacement and patellar tilt angle. The nonparametric Wilcoxon test was utilized for statistical analysis of data resulting from the static and kinematic studies in both groups. Nonparametric Mann-Whitney test was utilized in the comparison between healthy volunteers and patients. RESULTS: Statistical analysis demonstrated significant differences (p < 0.05) between static and kinematic magnetic resonance imaging for the three parameters evaluated in both groups. Among the patients the differences between static and kinematic measurements were greater than those found in the volunteers, at 30° and 20° flexion, with bisect offset and lateral patellar displacement. CONCLUSION: Static and kinematic magnetic resonance imaging, when performed in association, demonstrated that the lateral forces being exerted on the patella are higher at a knee flexion at the range between 20° and 30°, particularly in individuals symptomatic for femoropatellar instability. Keywords: Knee; Knee joint; Patella; Patellofemoral pain syndrome; Magnetic resonance imaging; Biomechanics; Chondromalacia patellae.Avaliação quantitativa das forças laterais da patela: ressonância magnética estática e cinemática. OBJETIVO: Avaliar a validade da ressonância magnética cinemática combinada com a ressonância magné-tica estática no estudo da articulação femoropatelar. MATERIAIS E MÉTODOS: Foram realizadas ressonân-cia magnética estática e ressonância magnética cinemática em 20 voluntários assintomáticos (40 joelhos) e em 23 pacientes (43 joelhos), em aparelho de configuração fechada de 1,5 tesla de campo. Os indivíduos foram posicionados na extremidade da mesa, em 30° de flexão. A translação patelar foi avaliada medindose o desvio da bissetriz, o deslocamento lateral da patela e o ângulo de inclinação da patela. Para a comparação entre os estudos estático e cinemático, foi utilizado o teste não-paramétrico de Wilcoxon. Para a comparação entre os voluntários e os pacientes, foi utilizado o teste de Mann-Whitney. RESULTADOS: Houve diferenças significantes entre a ressonância magnética estática e a ressonância magnética cinemática (p < 0,05) nos três parâmetros utilizados. No grupo dos pacientes, as diferenças entre a ressonância magnética estática e a ressonância magnética cinemática foram maiores que nos voluntários a 20° e a 30° de flexão, com o desvio da bissetriz e com o deslocamento lateral da patela. CONCLUSÃO: A combinação da ressonância magnética estática e ressonância magnética cinemática evid...

A Word of Caution for Future Studies in Patellofemoral Pain: A Systematic Review With Meta-analysis

“…Thirty studies received a score of 1 (partial) for Q4. ‖ Unable to assess was frequently indicated for questions regarding the main outcome measures’ accuracy (Q11) and the recruitment timeline (Q12), as they were scored affirmatively for 13 (32.5%) ¶ and 4 (10%) 38,45,47,77 studies, respectively. An attempt to blind researchers measuring the primary outcomes (Q14) was mentioned in only 4 studies (10%).…”

“…Out of the 40 studies included in this review, 21 evaluated PFP_iso # ; 10 evaluated PFP_dis (ie, history of dislocation, “instability,” or “subluxation”) ** ; 1 study included 2 isolated patient populations 67 ; and 8 allowed for a patient cohort of mixed diagnoses (PFP_iso and PFP_dis). 3,24,49,50,56,57,71,77 As highlighted by the quality assessment (Appendix Table A2, Q11, available online), two-thirds of the studies did not effectively describe the kinematic measures used. Surprisingly, knee angle was the measurement most often neglected, with only 10 studies †† providing an anatomic definition for it.…”

“…Surprisingly, knee angle was the measurement most often neglected, with only 10 studies †† providing an anatomic definition for it. Four studies 6,44,47,77 did not measure it; 10 studies ‡‡ used a locating device or goniometer to measure knee angle, but did not provide an anatomic definition; and the remaining 16 §§ failed to report how the knee angle was measured.…”

“…In 23 studies, ‖‖ a single axial image was used to measure patellar position. The use of multiple axial slices was adopted by 5 other studies, 1,6,21,45,77 while 10 studies ¶¶ adopted 3-dimensional techniques for consistency in bony reference landmarks. Two studies used 2D axial imaging planes, but did not define if single or multiple planes were used (Table 1).…”

“…A total of 22 patellar shift outcome metrics from studies within the review. Metrics: BSO, bisect offset (BSO1, 66 BSO1*, 1 BSO2, 44 BSO2*, 6 BSO3* 21 ); CA, congruence angle 40 ; LD, lateral distance 41 ; LPD, lateral patellar displacement (LPD1, 36 LPD2, 47 LPD2*, 6 LPD3*, 77 LPD4 14 ); LS, lateral shift 51 ; PFD*, patellar femoral displacement 56 ; PLCI, patella–lateral condyle index 32 ; POP, patellar offset position 4 ; subluxation. 69 The five 3-dimensional (3D) model metrics are not included (3D Shift1, 38 3D Shift2, 73 3D Shift3, 35 3D Shift4, 76 3D Shift5 15 ).…”