ABNORMAL PATTERNS OF KNEE MEDIO-LATERAL DEVIATION (MLD) ARE ASSOCIATED WITH PATELLOFEMORAL PAIN (PFP) IN CYCLISTS 322

Abstract

The aetiology of PFP in cyclists is not well understood. The aim of this study was to document the relationship between PFP and abnormal patterns of knee movement during cycling. Eighteen cyclists were recruited and eight (E, n=8) fulfilled the diagnostic criteria for PFP in 12 knees (bilateral pain in 4 subjects)(KP, n=12). Twelve controls (C, n=12) were pain free in 24 knees(KC, n=24). Subjects in the E and C groups had similar age (years)[mean(SD)][E, 27(9); C, 29(9)], height (cm) [E, 179(8); C, 184(5)], and body weight (kg)[E, 75(9); C, 80(5)]. Using high speed two-dimensional video analysis, reflective markers placed on the knees of all the subjects were filmed during cycling (>20revs). Subjects used their own cycling shoes and bicycles which were mounted on rollers. The movement of the reflective markers was plotted on a screen, digitised and measured. The patterns of knee movement [normal linear(NL), deviated oval (DO), deviated figure of eight (DF), deviated combined(DO+DF)] and the average medio-lateral deviation (MLD) of the knees was recorded. Prior to the study, the repeatability of this technique was established (r=0.93). The frequency of patterns of knee deviation in the KP and KC groups is depicted in Table 1. The MLD [mean(SD)] (mm) of the KP [14(5)] was greater than in the KC group[8(3)] (p<0.001). This study shows that PFP in cyclists is associated with non-linear patterns of knee movement and excessive MLD of the knee. Correcting non-linear patterns and decreasing the MLD may be important in the management of PFP in cyclists.